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Lecture Notes in Networks and Systems 233
Isak Karabegović Editor
New Technologies, Development and Application IV
Lecture Notes in Networks and Systems Volume 233
Series Editor Janusz Kacprzyk, Systems Research Institute, Polish Academy of Sciences, Warsaw, Poland Advisory Editors Fernando Gomide, Department of Computer Engineering and Automation—DCA, School of Electrical and Computer Engineering—FEEC, University of Campinas— UNICAMP, São Paulo, Brazil Okyay Kaynak, Department of Electrical and Electronic Engineering, Bogazici University, Istanbul, Turkey Derong Liu, Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, USA; Institute of Automation, Chinese Academy of Sciences, Beijing, China Witold Pedrycz, Department of Electrical and Computer Engineering, University of Alberta, Alberta, Canada; Systems Research Institute, Polish Academy of Sciences, Warsaw, Poland Marios M. Polycarpou, Department of Electrical and Computer Engineering, KIOS Research Center for Intelligent Systems and Networks, University of Cyprus, Nicosia, Cyprus Imre J. Rudas, Óbuda University, Budapest, Hungary Jun Wang, Department of Computer Science, City University of Hong Kong, Kowloon, Hong Kong
The series “Lecture Notes in Networks and Systems” publishes the latest developments in Networks and Systems—quickly, informally and with high quality. Original research reported in proceedings and post-proceedings represents the core of LNNS. Volumes published in LNNS embrace all aspects and subfields of, as well as new challenges in, Networks and Systems. The series contains proceedings and edited volumes in systems and networks, spanning the areas of Cyber-Physical Systems, Autonomous Systems, Sensor Networks, Control Systems, Energy Systems, Automotive Systems, Biological Systems, Vehicular Networking and Connected Vehicles, Aerospace Systems, Automation, Manufacturing, Smart Grids, Nonlinear Systems, Power Systems, Robotics, Social Systems, Economic Systems and other. Of particular value to both the contributors and the readership are the short publication timeframe and the world-wide distribution and exposure which enable both a wide and rapid dissemination of research output. The series covers the theory, applications, and perspectives on the state of the art and future developments relevant to systems and networks, decision making, control, complex processes and related areas, as embedded in the fields of interdisciplinary and applied sciences, engineering, computer science, physics, economics, social, and life sciences, as well as the paradigms and methodologies behind them. Indexed by SCOPUS, INSPEC, WTI Frankfurt eG, zbMATH, SCImago. All books published in the series are submitted for consideration in Web of Science.
More information about this series at http://www.springer.com/series/15179
Isak Karabegović Editor
New Technologies, Development and Application IV
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Editor Isak Karabegović Academy of Sciences and Arts of Bosnia and Herzegovina Sarajevo, Bosnia and Herzegovina
ISSN 2367-3370 ISSN 2367-3389 (electronic) Lecture Notes in Networks and Systems ISBN 978-3-030-75274-3 ISBN 978-3-030-75275-0 (eBook) https://doi.org/10.1007/978-3-030-75275-0 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland
Interdisciplinary Research of New Technologies, their Development and Application
This book features papers focusing on the implementation of new and future technologies, which were presented at the International Conference on New Technologies, Development and Application, held at the Academy of Science and Arts of Bosnia and Herzegovina in Sarajevo on 24–26 June 2021. It covers a wide range of future technologies and technical disciplines, including complex systems such as Industry 4.0; patents in industry 4.0; robotics; mechatronics systems; automation; manufacturing; cyber-physical and autonomous systems; sensors; networks; control, energy, renewable energy sources; automotive and biological systems; vehicular networking and connected vehicles; effectiveness and logistics systems, smart grids, nonlinear systems, power, social and economic systems, education, IoT. Majority of organized conferences are usually focusing on a narrow part of the issues within a certain discipline while conferences such these are rare. There is a need to hold such conferences. The value of this conference is that a various researchers, programmers, engineers and practitioners come to the same place where ideas and latest technology achievements are exchanged. Such events lead to the creation of new ideas, solutions and applications in the manufacturing processes of various technologies. New coexistence is emerging, horizons are expanding, unexpected changes and analogies arise. Best solutions and applications in technologies are critically evaluated. The first chapter covers mechanical design, Industry 4.0, robotics, cyber-physical systems, mechatronic systems, automation of production processes, 3D printing, advanced production and metallurgy. The first article gives analysis of service robots and artificial intelligence in diagnostics and treatment in medicine. The second article presents attitude design of controller for micro-satellites. This article aims to evaluate the control torques needed to ensure the attitude control of a micro-satellite. The primary disturbance torques, which act on the satellite varying its attitude and the interaction between the satellite and Earth, is considered. Several simulations have been conducted in the multi-body simulator Simscape. The next article discusses improving the accuracy of micro-hardness measurement of nano-electronic elements by the silicic probes of atomic force microscopy that is modified by carbon coverage. One of the articles gives an overview of intelligent v
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component development for gas turbine by using 3D printing at Siemens. This article discusses additive manufacturing and how Siemens energy is mainly using this technology for prototyping, manufacturing, repair of gas turbine components and spare part manufacturing. Several articles discuss the application of Industry 4.0. The last article is about ensuring the life cycle of objects on the basis of a signature approach. The second chapter covers computer science, information and communication technologies, Internet of Things, cyber-security. The first article explains time series prediction in software-defined network using deep learning. Researching the tuning of RNN hyper-parameters, this article examined time window for time series past data, batch size of analysed data, as well as time window for prediction of time series values in future, number of epochs and lastly steps per epoch for an RNN training process. The second article is about procedural content generation of custom tower defence game using genetic algorithms. Another article provides use of neuro-fuzzy approach in assessing the quality of knowledge. The last articles gives information about technology solutions and challenges for healthy urban environment through smart cities which are designed and based on complex and intelligent digital networks, trying to connect citizens, governments, buildings and objects that exchange information. Cloud-based software apps acquire, manage, and analyse this data and transform it into real-time intelligence that improves the quality of life. The third chapter is devoted to traffic and transport systems, logistics and intelligent systems. The chapter starts with providing multimodal traveller information cross-border journey planners approach. The second article is about user's perception of innovative e-mobility services. This article explains that mobility becomes an essential need in urban areas and that demand for existing transport modes upgrade is growing. To improve the overall quality of living in urban areas and to reduce the impact of regular traffic (pollution, noise emission, etc.), it is essential to widen mobility perspectives and possibilities. Another article explains the influence of introduction and integration of new technologies on processes in postal traffic. The first article explains visual deep learning-based mobile robot control and novel weighted fitness function-based image registration model. Last article explains application of multilevel integration model for unmanned aerial vehicles in traffic incident management processes. The fourth chapter is devoted to new technologies in the energy, fluids, power quality and advanced electrical power systems. The first article is about measuring velocity and temperature in leakage flows of oil-free rotary positive displacement machines. The article shows that main issues affecting reliability and efficiency of rotary oil-free positive displacement machines (PDMs) are the size of the clearance gaps between the rotating and stationary parts of a machine. It is desired to reduce these gaps in order to improve efficiency. but due to thermal growth. these can become too small and cause catastrophic failure. This article focuses on developing an experimental setup that can measure the velocity and temperature fields at the variety of operating conditions. The second article is about advantages of pump-controlled electro-hydraulic actuators. The article presents comparison
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between electro-hydraulic actuators (EHA), electro-mechanical cylinder systems (EMC) and common hydraulic system (CHC). Another article explains potential for energy savings by maintaining correct tyre pressure. One work is about a new approach for long-term testing of new hydraulic fluids. The fifth chapter is devoted to new methods in the agriculture, ecology and chemical processes of a wide range of topics: TiO2-based nano-composites for photocatalytic degradation of dyes and drugs, a novel device for the soil sterilizing in sustainable agriculture, numerical simulation of a cryogenic plant for the cooling of mashed grapes, determination of heavy metals in wild mushrooms from Western Bosnia, the influence of wastewater on the physical and chemical parameters of the river Bregava, digital transformation of agriculture: state in the government sector of Bosnia and Herzegovina or work with a topic application of nanotechnology in food engineering. The sixth chapter focuses on the field of geodesy, construction, new materials and sustainable innovation and others. The first article is about application of life cycle assessment in investigation of Šeher-Ćehajina ćuprija (a masonry bridge). Life cycle assessment (LCA) has been identified as a powerful tool which takes into account economic, environmental and socio-cultural impacts. The benefits of this approach are seen in its exhaustiveness, standardization and international recognition. This article provides information and elaborates reasons for taking into account environmental aspects in the bridge management system. The second article focuses on development and testing of microporous hydrophobic and oleophobic membranes. The following article is SCAN-TO-BIM procedure for an old industrial plant. One of the articles describes wind speed defining methodology applied in Bosnia and Herzegovina. Historical data for wind in Bosnia and Herzegovina is analysed with focus on type of instruments and mechanisms of measurements in period of 1961 to 1990 in system of hydrometeorological service in B&H. Detailed approach on system and methodology of measurement, collection and quality control of wind data gives as full picture for calculation of wind load. The seventh chapter covers economics, e-business and entrepreneurships. The chapter starts with agritech—possibilities for women economic empowerment in Bosnia and Herzegovina. Second article gives analysis of dynamics and models of innovative development of federal districts of Russia in the context of neo-industrial challenges. The first article is about process of technicizing the world, technoculture and technology as a medium. Last article is about illustrations of selected models and optimal project plans. The whole content of this book is intended to a wide range of technical systems: different technical disciplines in order to apply the latest solutions and achievements in technologies and to improve manufacturing processes in all disciplines where systemic thinking have a very important role in the successful understanding and building of human, natural and social systems. We hope this content will be the first in a series of publications that is intended to the development and implementation of new technologies in all industries. Isak Karabegović
Contents
New Technologies in Mechanical Engineering, Metallurgy, Mechatronics, Robotics and Embedded Systems Service Robots and Artificial Intelligence for Faster Diagnostics and Treatment in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Isak Karabegović, Ermin Husak, Safet Isić, Edina Karabegović, and Mehmed Mahmić Attitude Controller Design for Micro-satellites . . . . . . . . . . . . . . . . . . . . Marco Claudio De Simone, Giuseppe Ventura, Angelo Lorusso, and Domenico Guida Improving the Accuracy of Microhardness Measurement of Nanoelectronic Elements by the Silicic Probes of Atomic-Force Microscopy, that is Modified by Carbon Coverage . . . . . . . . . . . . . . . . Maksym Bondarenko, Victor Antonyuk, Iuliia Bondarenko, Iryna Makarenko, and Sergii Vysloukh An Experimental Study of the Influence of Mounting Errors on the Load Distribution Along the Face Width in a Spur Bevel Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Viktor Ivanov, Svitlana Ivanova, Galyna Urum, and Dmytro Purich Numerical and Experimental Stress Analysis of a Thin-Walled Cylindrical Tank with a Flat Bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . Elmedin Mesic, Muamer Delic, Nedim Pervan, Adis J. Muminovic, and Vahidin Hadziabdic Analytical Calculation and FEM Analysis of Single Girder Bridge Crane Made Out of Hot-Rolled Profiles . . . . . . . . . . . . . . . . . . . . . . . . . Enis Muratovic, Mirsad Colic, Adil Muminovic, and Isad Saric Size and Topology Optimization of Structures . . . . . . . . . . . . . . . . . . . . Ermin Husak and Mehmed Mahmić
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Analysis of Impact of Possibilities of Modern Computers on Applicability of Combinatorial Optimization . . . . . . . . . . . . . . . . . . . Safet Isić, Munib Obradović, and Semir Mehremić
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Hexacopter Design and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Isad Saric, Adnan Masic, and Muamer Delic
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Internet of Robotic Things . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Samir Vojić
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Development of the Concept of the Integrated Hydraulic System of the Knee Prosthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Remzo Dedić, Želimir Husnić, Faris Ustamujić, and Zlata Jelačić Hybrid Vibration Control Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Semir Mehremić, Safet Isić, and Munib Obradović
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Object Classification in an Intelligent Robotic Cell Using Deep Learning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Lejla Banjanovic-Mehmedovic and Azra Gurdić Design and Development of Street Lamp . . . . . . . . . . . . . . . . . . . . . . . . 113 Isad Saric, Enis Muratovic, and Senad Rahimic Development and Design of a Machine for Hybrid Manufacturing . . . . 121 Jasmin Smajic, Adis J. Muminovic, Isad Saric, and Adil Muminovic Interactive Mechanical Donation Box . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 Alma Žiga and Belmin Hinović Multiaxis Machining of Fork-Type Parts: Fixture Design and Numerical Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 Vitalii Ivanov, Ivan Dehtiarov, Artem Evtuhov, Ivan Pavlenko, and Anatolii Ruban Rolling Ball Sculpture as a Mechanical Design Challenge . . . . . . . . . . . 153 Alma Žiga and Derzija Begic-Hajdarevic Features of Overload Protection for Bridge Type Cranes . . . . . . . . . . . 162 Tonkonogyi Volodymyr, Semenyuk Volodymyr, Sydorenko Iihor, Lingur Voleriy, and Vudvud Oleksanr Reverse Engineering in the Remanufacturing: Metrology, Project Management, Redesign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Viktor Ivanov, Lubomir Dimitrov, Svitlana Ivanova, and Mariia Volkova Investigation of the Influence of Tapered Thread Profile Accuracy on the Mechanical Stress, Fatigue Safety Factor and Contact Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 Volodymyr Kopei, Oleh Onysko, Zinivii Odosii, Lolita Pituley, and Andrii Goroshko
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Structure and Strength Properties of Al-Cr Alloys Obtained by Quenching from a Liquid State and Laser Surface Reflow . . . . . . . . 186 Aleksandr B. Lysenko, Tatyana V. Kalinina, Sergei V. Gubarev, Iryna V. Zagorulko, and Yana V. Vishnevskaya Simulation of the Operating Modes of the Proposed Equipment When Loading the External Circuit of the Working Hydraulics in Tractor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 Juraj Jablonický, Peter Kožuch, Ľubomír Hujo, Romana Janoušková, and Matej Michalídes Properties Evaluation of New Biodegradable Fluid During Accelerated Durability Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 Juraj Tulík, Ľubomír Hujo, Juraj Jablonický, Jozef Nosian, and Jerzy Kaszkowiak Plasticity Studies During Deformation Under Conditions of Significant Negative Values of the Stiffness Coefficient of the Stress State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 Ihor Shepelenko, Yuri Tsekhanov, Yakiv Nemyrovskyi, Pavlo Eremin, and Oleh Bevz Parameters of Pipe Narrowing by Radial Forging with Inner Thread Tightening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 Himzo Đukić and Mirna Nožić Research of the Surface Roughness Parameters After End Milling . . . . 231 Matej Kljajo and Danijel Šogorović The Electro-Pneumatic System as a Cyber - Physical System: The Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 Elvis Hozdić and Zoran Jurković Role of Industry 4.0 in Albanian Industry Transformation: An Integrated Understanding of Industry 4.0 . . . . . . . . . . . . . . . . . . . . 251 Ilo Bodi, Erald Piperi, Eralda Xhafka, Jonida Teta, and Merita Kosta Challenges of Albanian Companies for Sustainable Development in the Era of Industry 4.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 Irma Shyle, Eralda Xhafka, and Jonida Teta Analysis of Innovation Activities in Georgia as a Major Factor in Application of the Industry 4.0 Concept . . . . . . . . . . . . . . . . . . . . . . 270 Raul Turmanidze, Predrag Dašić, and Giorgi Popkhadze Dynamic Simulation of Worm Gears Using CAD Applications . . . . . . . 278 Alina Bianca Pop and Aurel Mihail Țîțu
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“ICDBY3D” Intelligent Component Development for Gas Turbine by Using 3D Printing at Siemens Energy AB Sweden . . . . . . . . . . . . . . 286 Pajazit Avdovic, Mineta Galijasevic, Vladimir Navrotsky, and Andreas Graichen A Comparison of the CMM and Measuring Scanner for Printing Products Geometry Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 Almira Softić, Hazim Bašić, and Kenan Baljić 3D Printing Solutions in the Fight Against Covid-19 Pandemic . . . . . . . 310 Milena Djukanovic, Mihailo Jovanovic, Nikola Pejovic, and Dejan Lutovac Measurement of NACA Airfoil Characteristic Parameters on 3D Printed Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 Kenan Varda, Ernad Bešlagić, and Nermina Zaimović-Uzunović Analysis and Improvement of Industrial Production Lines Assisted by 3D Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333 Erald Piperi, Ilo Bodi, Dea Sinoimeri, Tatjana Spahiu, and Jorgaq Kaçani Experimental-Numerical Analysis of Hot Forging Process with Monitoring of Heat Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341 Marko Popović, Vesna Mandić, Marko Delić, and Vladimir Pavićević Supplement to the Standard VDI/DGQ 3442 with Gage R&R Study . . . 350 Branko Štrbac, Miloš Ranisavljev, Milan Zeljković, Miloš Knežev, and Miodrag Hadžistević Surface Characterization of the Cobalt-Based Alloy Stents Fabricated by 3D Laser Metal Fusion Technology . . . . . . . . . . . . . . . . . 357 Dmytro Lesyk, Oleksandr Lymar, and Vitaliy Dzhemelinkyi Analysis of the Behavior of the Ash Depending on the Temperature of Combustion and Air Supply System . . . . . . . . . . . . . . . . . . . . . . . . . 365 Nihad Hodzic, Anes Kazagic, and Kenan Kadic Simulation Analysis of Underground Coal Mine Ventilation Systems Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 Edisa Nukić and Edin Delić Influence of the Human Body’s Center of Gravity on Some Aspects of Lower Limb Movement During CAD Modeling . . . . . . . . . . . . . . . . . 385 Sydorenko Ihor, Tonkonogyi Volodymyr, Bovnegra Liubov, Salii Vera, and Kovban Sofia Optimization and Yield of Low Quality and Small Sized Diameter Oak (Quercus robur L.) Logs in Production of Rough Elements . . . . . . 394 Selver Smajić, Juraj Jovanović, Josip Ištvanić, and Murčo Obućina
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The Application of DMAIC Lean Six Sigma Methods in Assembly Technology Design of Filter W 1022/LE 19172 . . . . . . . . . . . . . . . . . . . 401 Ismar Alagić Total Quality in a Serial Industry - The Concept of a Closed-Loop in a Total Autonomous Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410 Aurel Mihail Ţîţu and Gusan Vasile Minitab Application as Statistical Tool for Lean Six Sigma . . . . . . . . . . 422 Ismar Alagić Mechanical - Insulating Method of Household and Industrial Waste Utilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431 Sviatoslav Kurnosov, Liubomyr Ropyak, Andriy Velychkovych, Tetiana Pryhorovska, and Vasyl Vytvytskyi Effect of the M-Phenylenediamine on the Tribotechnical and NVH Characteristics of the Frictional Composite Materials Based on PTFE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442 Sergej N. Bukharov, Vitalix K. Merinov, Vladimir P. Sergienko, Anfrey Ya. Grigoriev, and Soyibjon S. Negmatov Advanced Sound Absorbing Materials to Reduce Noise and Improve the Environmental Situation in Production Facilities and Transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450 Sergey N. Bukharov, Anastasiya S. Tuleiko, Vladimir P. Sergienko, Nodira S. Abed, and Alexander R. Alexiev Ensuring the Life Cycle of Objects on the Basis of a Signature Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458 Sergiy Kovalevskyy, Olena Kovalevska, Milan Radosavljević, and Maja Anđelković Dependence Analysis of the Friction Force from Time of Biocompatible Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469 Raul Turmanidze and Giorgi Popkhadze Electrical Engineering, Computer Science, Information and Communication Technologies, Control Systems Time Series Prediction in Software – Defined Network Using Deep Learning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481 Jasenko Topic, Lejla Banjanovic-Mehmedovic, and Suad Kasapovic Procedural Content Generation of Custom Tower Defense Game Using Genetic Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493 Vid Kraner, Iztok Fister Jr., and Lucija Brezočnik
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Information Technology for Implementation the Functional Modeling of a Technical Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 504 Viktoriia Antypenko, Viktor Nenia, Anna Marchenko, Bohdan Antypenko, and Anton Kovpak Thermal Imager Hardware and Software Design Concept . . . . . . . . . . . 513 James Brennan and Migdat Hodzic The Rise of Distributed Artificial Intelligence Through Shared Data and Cloud Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522 Aurel Mihail Țîțu and Alexandru Stanciu Use of Neuro-Fuzzy Approach in Assessing the Quality of Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530 Rosa U. Stativko Real-Time Intelligent Information Systems to Support More Efficient Work of Construction Companies . . . . . . . . . . . . . . . . . . . . . . 539 Mladen Radivojević, Merima Šahinagić-Isović, Muharem Kozić, and Davor Radivojević Disturbance Observer Based Control of Shunt Active Power Filter . . . . 549 Sevkuthan Kurak Features Formation Autonomous Power Supply Systems of Critical Infrastructure Objects Based on Induction Generator . . . . . . . . . . . . . . 563 Volodymyr Chenchevoi, Sergii Firsov, Olha Chencheva, Andrii Perekrest, and Vira Shendryk Information Support of Power Quality Control Systems . . . . . . . . . . . . 570 Ivan Abramenko, Sergii Tymchuk, Vira Shendryk, Sergii Shendryk, and Stanislav Radchenko Analysis of X-Ray Images of the Lungs Using a Neural Network . . . . . 578 Olha Pronina, Tetiana Levytska, Irina Fedosova, and Olena Piatykop Waste Management System Automized Through IoT . . . . . . . . . . . . . . 587 Aleksander Biberaj, Igli Tafaj, Alban Rakipi, Renalda Kushe, and Ezmerina Kotobelli Security of Automated Teller Machines (ATM’s) . . . . . . . . . . . . . . . . . . 596 Aleksander Biberaj, Igli Tafaj, Olimpjon Shurdi, Elson Agastra, and Alban Rakipi Implementation of New Technologies in the Promotion of the Cultural Routes - Practices and Challenges . . . . . . . . . . . . . . . . . 607 Marija Orlandic and Andjela Jaksic-Stojanovic Comb-Based Decimation Filter with Improved Aliasing Rejection in All Folding Bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615 Gordana Jovanovic Dolecek and Isak Karabegovic
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Industrial Revolution and Employee Motivation Evolution . . . . . . . . . . 624 Mirha Bičo Ćar, Munira Šestić, Savo Stupar, and Emir Kurtović Mobile Application mTemperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632 Suad Sućeska The Importance of Machine Learning in Intelligent Systems . . . . . . . . . 638 Savo Stupar, Mirha Bičo Ćar, Emir Kurtović, and Grujica Vico Dictionary Based Brute Force Attack – Study Case of Montenegro and China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 647 Milena Djukanovic, Lazar Novicevic, Liehuang Zhu, and Peng Jiang Information Technology Solutions and Challenges for Healthy Urban Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653 Samir Lemeš Intelligent Transport Systems, Logistics, Traffic Control Providing Multimodal Traveler Information Cross-Border Journey Planners Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665 Sadko Mandžuka User’s Perception of Innovative E-Mobility Services . . . . . . . . . . . . . . . 673 Miroslav Vujic, Luka Dedic, and Sadko Mandzuka Flight Mechanics, Aerodynamics and Modelling of Quadrotor . . . . . . . 681 Đorđe Jevtić, Jelena Svorcan, and Radoslav Radulović The Influence of Introduction and Integration of New Technologies on Processes in Postal Traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 690 Amel Kosovac, Ermin Muharemović, Mladenka Blagojević, and Adisa Medić Safety Culture in the Function of Optimization of Railway Safety Management System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 700 Aida Kalem, Osman Lindov, and Edvin Šimić Design and Development of a Holonomic Mobile Robot for Material Handling and Transportation Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 709 Lazar Đokić, Aleksandar Jokić, Milica Petrović, and Zoran Miljković New Technologies and Optimization of the Safety Management System with Implementation in B&H Airspace . . . . . . . . . . . . . . . . . . . 717 Šimić Edvin, Lindov Osman, and Kalem Aida Proposal of Conceptual Model for Management Improvement of Dangerous Places on the Road Network . . . . . . . . . . . . . . . . . . . . . . 724 Adnan Omerhodžić, Osman Lindov, and Amel Kosovac
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Strengthening Engineering Competencies for the Composite Molding Stands Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 737 Margarita V. Stoyanova, Alla E. Brom, and Andrey D. Novikov Visual Deep Learning-Based Mobile Robot Control: A Novel Weighted Fitness Function-Based Image Registration Model . . . . . . . . . 744 Aleksandar Jokić, Milica Petrović, Zbigniew Kulesza, and Zoran Miljković Application of Multilevel Integration Model for Unmanned Aerial Vehicles in Traffic Incident Management Processes . . . . . . . . . . . . . . . . 753 Pero Škorput, Dario Medić, and Lucija Bukvić New Technologies in the Energy, Fluids, Power Quality, Advanced Electrical Power Systems On Measuring Velocity and Temperature in Leakage Flows of Oil Free Rotary Positive Displacement Machines . . . . . . . . . . . . . . . . . . . . . 763 Brijeshkumar Patel, Ahmed Kovacevic, and Aleksander Krupa Advantages of Pump Controlled Electro Hydraulic Actuators . . . . . . . . 774 Samo Goljat, Darko Lovrec, and Vito Tič Pressure Drop Development on Hydraulic Filter as an On-Line Condition Monitoring Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 781 Vito Tič and Darko Lovrec A New Approach for Long-Term Testing of New Hydraulic Fluids . . . . 788 Darko Lovrec and Vito Tič Manufacturing Analysis of High-Pressure Gear Pumps: A Case Study from Serbia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802 Milutin Živković, Predrag Dašić, Milan Radosavljević, and Maja Anđelković Assessment of the Impact of Automatic Parking on Emissions of Harmful Substances in the Green Logistic System . . . . . . . . . . . . . . . 815 Svitlana Filyppova, Liubov Bovnegra, Olena Chukurna, Oleksandr Vudvud, and Vitalii Dobrovolskyi Numerical Simulation of Rayleigh-Bernard Convection Affected by Lower Wall Temperature Variation . . . . . . . . . . . . . . . . . . . . . . . . . 823 Sadoon Ayed Potential for Energy Savings by Maintaining Correct Tyre Pressure . . . 833 Mirsad Trobradović, Almir Blažević, Vahidin Hadžiabdić, Dževad Bibić, and Boran Pikula Numerical Investigation of the Contamination Thickness Influence to the Flow Parameters for Multi-hole Orifice Flow Meter . . . . . . . . . . 840 Amra Hasečić, Siniša Bikić, and Ejub Džaferović
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New Technologies in Agriculture, Ecology, Chemical Processes TiO2 – Based Nanocomposites for Photocatalytic Degradation of Dyes and Drugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 851 Amra Bratovcic A Novel Device for the Soil Sterilizing in Sustainable Agriculture . . . . . 858 Andrea Formato, Raffaele Romano, and Francesco Villecco Numerical Simulation of a Cryogenic Plant for the Cooling of Mashed Grapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 866 Raffaele Romano, Andrea Formato, and Francesco Villecco Intermolecular Interactions in Complex Systems “Polyamide-Silica Gel”: The Quantum-Chemical Interpretation . . . . . . . . . . . . . . . . . . . . . 875 Andrey Tokar, Oleg Kabat, Olga Chigvintseva, and Svetlana Belošević Estimating the Health Risk of Heavy Metals in Edible Plants to the General Population in Sarajevo, B&H . . . . . . . . . . . . . . . . . . . . . 883 Aida Sapcanin, Ekrem Pehlic, Selma Korac, Emina Ramic, and Belma Pehlivanovic Determination of Heavy Metals in Wild Mushrooms from Western Bosnia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 889 Aida Sapcanin, Ekrem Pehlic, Emina Ramic, Selma Korac, and Belma Pehlivanovic In Silico Analysis of Scopoletin Interaction with Potential SARS-CoV-2 Target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 897 Tarik Ikanovic, Emir Sehercehajic, Belmina Saric, Nikolina Tomic, and Rifat Hadziselimovic The Influence of Wastewater on the Physical and Chemical Parameters of the River Bregava . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904 Dalila Ivanković, Merima Šahinagić–Isović, Fuad Ćatović, and Almir Šestan Dramatization as a Methodicalprocedure in Developing Ecological Habits of Preschool Children . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 912 Mina Mavrić and Ibro Skenderović Morphometric Characteristics of alpine Newt–Ichthyosaura alpestris (Laurenti, 1768) from Lake Hrid (Montenegro) . . . . . . . . . . . . . . . . . . . 922 Isat Skenderović, Eldar Tanović, and Ibro Skenderović Analysis of Technologies and Technological Process of Forest Harvesting – Case Study Tuzla Canton . . . . . . . . . . . . . . . . . . . . . . . . . 930 Velid Halilović, Jusuf Musić, Jelena Knežević, and Edin Jusufović
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Microbic Toxins in Cereals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 945 Huska Jukić, Ivana Radočaj, Marijana Blažić, Ibrahim Mujić, and Sandra Zavadlav Recent Developments on Metal Oxide - Based Gas Sensors for Environmental Pollution Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 952 Amra Bratovcic Consideration of the Possibility of Using Ozone in the Treatment of Drinking Water in the “Tilava” Water Supply System . . . . . . . . . . . 964 Jovana Blagojević, Goran Orašanin, and Stojan Simić Digital Transformation of Agriculture: State in the Government Sector of Bosnia and Herzegovina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 972 Grujica Vico, Danijel Mijić, Radomir Bodiroga, and Savo Stupar Application of Nanotechnology in Food Packaging . . . . . . . . . . . . . . . . 979 Almedina Ibrahimović, Amina Stambolić, and Enisa Omanović-Mikličanin Application of Nanotechnology in Food Engineering . . . . . . . . . . . . . . . 985 Maid Ćibo, Amina Stambolić, and Enisa Omanović-Mikličanin New Technologies in Civil Engineering, Architecture, Quality Control Application of Life Cycle Assessment in Investigation of Šeher-Ćehajina ćuprija (A Masonry Bridge) . . . . . . . . . . . . . . . . . . . 1001 Naida Ademović Development and Testing of Microporous Hydrophobic and Oleophobic Membranes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1011 Mario Krzyk and Darko Drev Scan-To-Bim Procedure for an Old Industrial Plant . . . . . . . . . . . . . . . 1019 Caterina Gabriella Guida, Andrea di Filippo, and Pierpaolo D’Agostino Satellite Thermography of Cities and Possibilities of Influence on Temperature Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1027 Admir Mulahusić, Nedim Tuno, Jusuf Topoljak, and Muamer Đidelija Between Technology and Ornament in Contemporary Building Envelope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1036 Slavica Stamatović Vučković and Sanja Paunović Žarić Urban Stormwater Management – New Challenges . . . . . . . . . . . . . . . . 1046 Suvada Šuvalija, Emina Hadžić, and Hata Milišić Spreadsheet Solution for Cost-Optimal Construction Scheduling Through Utilization of Internet-Based Solvers . . . . . . . . . . . . . . . . . . . . 1055 Borna Dasović and Uroš Klanšek
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Sustainable Composite Materials with Industrial Waste Red Mud – An Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1063 Marko Ćećez, Merima Šahinagić – Isović, and Fuad Ćatović Comparison of the Steel N and V Lattice Structure of the Hall by Structural Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1069 Rašid Hadžović and Muamera Horozović Wind Speeddefining Methodology Applied in Bosnia and Herzegovina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1077 Rašid Hadžović and Bakir Krajinović Application of Joints in Modern and Traditional Construction . . . . . . . 1085 Sanela Klarić and Venera Simonović Floodplain Mapping Using HEC-RAS and Lidar Data: A Case Study of Bistrica River (Vrbas River Basin in B&H) . . . . . . . . . . . . . . . 1093 Hata Milišić, Emina Hadžić, Suvada Šuvalija, and Emina Jahić Economics, E-Business, Entrepreneurships Agritech – Possibilities for Women Economic Empowerment in Bosnia and Herzegovina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1107 Munira Šestić, Zijada Rahimić, Mirha Bičo Ćar, and Amila Pilav-Velić Analysis of Dynamics and Models of Innovative Development of Federal Districts of Russia in the Context of Neo-industrial Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1114 Maria S. Starikova, Yury A. Doroshenko, and Victoria N. Riapuhina Magnitude of Covid-19 Pandemic Impact on Entrepreneurial Companies’ Operations in Developing Countries . . . . . . . . . . . . . . . . . . 1127 Elvir Čizmić, Munira Šestić, Anes Hrnjic, and Senad Softić Gender Differences of Entrepreneurial Business attitudes in the Crisis Caused by Covid-19 Global Pandemic: Evidence from Bosnia and Herzegovina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1134 Munira Šestić, Elvir Čizmić, Senad Softić, and Anes Hrnjic Analysis of Effective Crisis Management and Crisis Communication in Public Sector Organizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1141 Merima Tanović, Đevad Šašić, Anis Ajdinović, and Elvir Čizmić The Role of Large Tech Companies in the Capital Market Recovery from the Covid-19 Crisis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1149 Azra Zaimovic and Lejla Dedovic
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The Process of Technicizing the World, Technoculture and Technology as a Medium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1158 Halima Sofradžija, Abdel Alibegović, Sarina Bakić, and Melika Arifhodžić Enterprise-based Support to Innovative Activities . . . . . . . . . . . . . . . . . 1166 Ivana Domljan and Vjekoslav Domljan Determinants of Market Orientation of Bosnia and Herzegovina Companies in the Food Processing Industry . . . . . . . . . . . . . . . . . . . . . . 1173 Emir Kurtović, Savo Stupar, Jasmin Sadović, and Mirha Bičo Ćar Modified Gauss-Type Competitive System . . . . . . . . . . . . . . . . . . . . . . . 1183 Zejd Imamović, Vahidin Hadžiabdić, Midhat Mehuljić, Jasmin Bektešević, and Dževad Burgić No Existence of Chaos in the System of Rational Difference Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1188 Jasmin Bektešević, Vahidin Hadžiabdić, Midhat Mehuljić, Adnan Mašić, and Adis J. Muminović The Minimum Cost Flow Problem (Mcfp-Cnf) Including Vechiles, Two Types of Times and Amount of Cargo with Maximum Time . . . . . 1196 Omer Kurtanović and Admir Kurtanović Illustrations of Selected Models and Optimal Project Plans . . . . . . . . . . 1205 Omer Kurtanović Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1219
New Technologies in Mechanical Engineering, Metallurgy, Mechatronics, Robotics and Embedded Systems
Service Robots and Artificial Intelligence for Faster Diagnostics and Treatment in Medicine Isak Karabegovi´c1(B) , Ermin Husak2 , Safet Isi´c3 , Edina Karabegovi´c2 , and Mehmed Mahmi´c2 1 Academy of Sciences and Arts, Bosnia and Herzegovina, St. Bistrik 7,
71000 Sarajevo, Bosnia and Herzegovina 2 University of Biha´c, 77000 Biha´c, Bosnia and Herzegovina 3 University Džemal Bijedi´c, 38000 Mostar, Bosnia and Herzegovina
Abstract. The development of new technologies such as information and communication technologies, electronics, sensor technology, etc. lead to the development of service robots and systems, which are used in all segments of human life. One of the most important roles of service robots today is application in the field of medicine. Service robots in medical institutions are used to perform simple or complex tasks. Simple tasks include deliveries of drugs, food or mail to medical facilities, while complex tasks include robotic systems used in operating rooms or even to perform operations using suitable robotic systems whose design and applied technology allow it, such as Zeus and Da Vinci systems. Service robots help doctors perform their tasks easier, safer, more accurately and faster. The paper illustrates examples of the application of service robots in diagnostics, radiation, surgery, remote treatment, rehabilitation, drug distribution, patient care and disinfection of rooms in medical institutions. The rapid development of new technologies had made it possible to free people from routine mental activities, and in the future more and more complex thought activities, such as: learning, analyzing, adapting, concluding, making decisions, etc. We come to the conclusion that there is a need for the application of artificial intelligence. The combination of service robots and artificial intelligence leads to the development of autonomous systems. Autonomous systems are developed in a targeted way so that they can surpass man himself in some properties, such as: physical strength, memory capacity, computational speed, parallel execution of several control actions, etc. The paper presents the role and application of artificial intelligence in diagnostics and treatment of various diseases. Keywords: Service robot · Artificial intelligence · Medicine · Diagnostics · Disease
1 Introduction In the last decade, the development and progress made in computer science, engineering, electrical engineering and mechatronics has enabled the development of an increasingly © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 3–20, 2021. https://doi.org/10.1007/978-3-030-75275-0_1
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sophisticated sensorimotor function that allows robots to adapt to constant changes in the environment. In addition, in 2016, artificial intelligence (AI) celebrated the 60th anniversary of the Dartmouth workshop which marked the beginning of the recognition of artificial intelligence as an academic discipline. Today, service robots are more easily integrated into the existing environment. The autonomy of service robots in the environment can be divided into observations, planning and execution of tasks, i.e. manipulation, navigation and cooperation [1–6]. The main idea of approaching and matching artificial intelligence and robotics is an attempt to optimize the level of autonomy through learning. In other words, this level of intelligence is nothing but the ability to predict the future in interaction with the world (either manipulating or navigating) or planning tasks. There are service robots that can perform special autonomous tasks by sensing the environment through integrated sensors or computer vision, and in the last decade computer systems have improved the quality of both readings [1, 43–48]. Artificial Intelligence and Robotics, UK-RAS Network, London, UK; [www.ukras.org] The application of artificial intelligence in robotics is important for perception, which is essential not only for planning but also for creating an artificial sense of self-awareness in robots, allowing robots to support interaction with other participants in the same environment. This feature is very important from the social point of view and is known as social robotics which includes two broad domains: human-robot interaction and cognitive robotics. These properties are very important in service robots used in medicine. From the medical point of view, robotics is still a relatively new field of research in the world and a large number of institutes and companies strive to conquer different styles and techniques to solve different procedures in medicine. This is a motive and challenge for many researchers trying to solve these tasks. Research shows that 87% of falls of the elderly result in a fracture. This information leads us to the fact that we must have trauma centers that have the ability to diagnose and take appropriate treatment very quickly and help the injured with expertise [7, 8]. However, orthopedics as a discipline is relatively conservative, but with great potential for improvement. With the development of information technologies and new materials, and robotic technology, there is now an opportunity to change that, and overcome problems that could not be solved before, but also to improve orthopedics and help patients recover quickly and return to normal lifeprior to injury. Orthopedics has been identified as particularly suitable for the application of service robots in this area, because bones are relatively rigid structures, and we have the abilities and techniques to register bone position and draw the right conclusion and treatment for further patient care. The use of service robots in endoscopic surgery has been shown to have a beneficial effect on patients with regard to reducing hospital stays. Postoperative pain is less and the patient returns to daily activities earlier. The introduction of service robots or surgical robotic systems is an attempt to overcome these technical difficulties and improve the work of surgeons. The advantages of operations using robotic systems compared to conventional operations in laparoscopy are: additional degrees of freedom of movement, the possibility of different movements, improved stability, visualization, surgical instruments and improved ergonomics for the surgeon [9, 10]. Certainly, it is important to mention that by applying these techniques, surgical procedures for elderly patients are less painful and postoperative recovery is significantly shorter. Today, service robots
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occupy a significant place in medicine. The advantages of these robots in revolutionary clinical practice are numerous: • • • • • •
application of diagnostic devices and tools for diagnostics and therapy, facilitated medical processes with precise guidance of instruments, increased safety and overall quality of the operation, improved patient care, faster and better rehabilitation, logistics in medical institutions is better with the use of service robots, etc.
In addition to the application of service robots in medicine, there has recently been application of technology driven by artificial intelligence in everyday life, so that it entered more aspects of the life of each individual. It is expected that artificial intelligence will change medical practice in hitherto unknown ways. However, many of its practical applications are still at the beginning and need to be better researched and developed. In the recent years, the increased level of computerization of clinical centers in medical institutions, more accessible standardized communication technology between medical institutions, data storage and increased scope of quality methods of diagnostic radiology are the cause of the explosion of available data, thus opening many opportunities to use artificial intelligence to diagnose and treat diseases. Researchers are working towards the use of artificial intelligence to analyze large amounts of health data and find patterns that could lead to new discoveries in medicine and improve individual diagnostics [11]. As misdiagnosis can be fatal for patients, intensive work is being done to significantly reduce the percentage of errors in the future with the help of artificial intelligence. It is believed that artificial intelligence could mostly help in solving the problems caused by labor shortages (it is well-known that there is shortage of more than five million doctors worldwide), while the institutions could become more efficient and ready to respond to the challenges of modern medicine.
2 Distribution of Service Robotic Systems in Medicine The classification of service robots in medicine by category and types of interactions has been adopted, so that service robots in medicine have the following classification: diagnostic systems, robot-assisted surgery and therapy, robotic rehabilitation systems and other robotic systems for use in medical institutions. Statistical data for the analysis of the trend of implementation of service robots in medical institutions were taken from the International Federation of Robotics (IFR), the UN Economic Commission for Europe (UNECE) and the Organization for Economic Co-operation and Development (OECD). Figure 1 presents the trends of the total application of service robots in medical institutions on annual basis for the period 2014–2020, as well as estimates of implementation by 2023 [2, 12–23]. The trend of implementation of service robots in medical institutions for healthcare services is shown in Fig. 1 and Fig. 2. Out of the total amount of sold and implemented service robots for professional services in 2019, service robots for medical use take about 5%. This is a small percentage and we believe that this percentage will have a growing
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Fig. 1. Implementation of service robots in medical institutions on annual basis for the period 2014–2020 and estimated implementation by 2023
Fig. 2. Implementation of service robots for medical services in 2019 [13]
trend in the coming years, based on the fact that our population is getting older, and we will need more services provided by robots to free medical workers for elderly care. There has been an increase of the investment in the development of robotic technology and development of new service robots for medical services and various purposes. Conclusion can be made based on the trend of sales and implementation of service robots for medical services shown in Fig. 1. We can conclude that the implementation of service robots for medical services in 2009 amounted to about 820 units, and in just ten years the trend increased to about 5.600 service robot units in 2019, which is an increase of about seven times. It is estimated that the trend will continue to grow in the coming years, so that the implementation of about 18.000 robot units is expected in 2023. It can be concluded that the implementation of service robots for medical services has been growing exponentially since 2014. Out of a total of 5% of service robots for medical services implemented in 2019, compared to their implementation in other areas, they were used for various medical services, as shown in Fig. 3 [2].
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Neurosurgery 6%
3% Orthopedics
11% 17%
17%
14% 32%
Endoscopy Mini intervenƟonal surgery
Point radiaƟon Colonoscopy
Fig. 3. Implementation of service robots for medical services by areas
Based on Fig. 3 we can conclude that the largest number of implementations of service robots in medicine is in regard to small intervention surgeries 32%, followed by orthopedics 17%, neurosurgery 11%, endoscopy 14%, radiation 17%, colonoscopy 6%, etc.(Karabegovi´c and Doleˇcek 2012, 115–162). The most relevant useful factors are: high quality of work and productivity, reduction of manual work, increased safety or risk avoidance, increased operational usability, temporary flexibility, new previously available facilities, conditions, etc.
3 Application of Service Robots in Medicine As we have seen, service robots are present in almost all branches of medicine, as shown in Fig. 3. The field of application of service robots in medicine is expanding every day, from the admission of patients until their complete recovery. Due to limitations, the paper will list only areas of medicine where service robots are represented. Diagnostics Robotic diagnostic devices can be located at a distance from the patient’s body, directly on the patient’s body, or enter the patient’s body. The world’s leading manufacturers of this type of equipment are: Accuray (USA), Medtronic (Germany), Robosoft (France), and Siemens (Germany). Accurey (USA) has patented a device called the Cyber Knife, installed in the UK at the famous Harley Street Clinic in London. This device is used to treat prostate cancer, which cannot be treated in any other way. This product has made a big step forward in the treatment of this type of disease. Cyber Knife provides a small dose of radiation to the tumor without further destroying healthy tissue. Three-dimensional tumor scanning is performed before treatment using a CT scanner, based on which the dose and radiation density are calculated. The radiation device is mounted on a robotic arm, so that it is possible to perform radiation of different strength and density from various positions according to a previously determined plan. In addition to the above, Cyber Knife is a robotic radiotherapy device that can treat many types of tumors, which was not possible with previous conventional methods. The machine is characterized by a programmed radiation dose from the appropriate position, without damaging the adjacent tissue [26, 37].
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Fig. 4. Service robots in the diagnostic center and robotic radiation systems [24]
Service robots for surgery Service robots can make the surgeon’s job easier because they achieve precision and accuracy, which leads to great improvement. We use service robots for the following purposes: • • • • •
to assist, hold, set and direct instruments, telesurgical options, orientation, positioning, application in surgical procedures.
Assistant functions are performed by a robotic arm, which is used to hold endoscopic cameras, and monitor and follow the movements of the surgeon with the help of a sensor system [2, 9–11]. Tele surgical devices allow the surgeon to use the robot as an extension of his own manipulative ability. Navigation devices provide feedback on the position of the appropriate instrument in the patient’s anatomy. Many service robots for surgery have been developed, and we list the most famous ones that are most represented. 3.1 DA VINCI Surgical System The DA VINCI robotic system is a sophisticated robotic platform designed to expand the capabilities of surgeons and enable the performance of complex operations using a minimally invasive approach [28]. The Da Vinci surgical system is a computer-enhanced minimally invasive surgical system consisting of three components: • InSite Vision System • Surgical Arm Cart containing two or three interactive robotic arms and EndoWrist instruments, and • Surgeon Console. This robotic surgical system uses Endo Wrist technology - small, computer-enhanced mechanical joints near the tip of the instrument that provide all the flexibility as a human wrist and forearm through a 10 mm hole in the human body (Fig. 5).
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Fig. 5. Da Vinci surgical system with designated components [2, 37]
3.2 ZEUS Surgical System The ZEUS surgical system, developed in 1995 by Computer Motion, Inc., was approved in 2002 for use in general and laparoscopic surgery (minimally invasive surgery within the abdominal cavity) with a patient and surgeon in the same room. Zeus is a surgical robot consisting of three robotic arms placed on a table, where one of them holds an AESOP (Automated Endoscopic System for Optimal Positioning), which provides a view of the internal operating field, while the other two hands hold surgical instruments. One of the standard components of the Zeus system is the HERMES control center, which uses voice recognition technology to control devices outside the sterile field [29]. The robotic arms are controlled by a surgeon, who sits behind a control console a few feet away from the patient. Visualization of the operating field is controlled by voice activation, while the robot’s hands are controlled by the movements of the surgeon’s hands and wrists. In addition, there are more than fifty medical instruments designed for the Zeus surgical system. It includes various scissors, grippers, dissectors, needle holders, stabilizers and scalpels. This robot has been used to assist surgeons with surgeries such as beating heart bypass surgery (Fig. 6).
a-Zeus console
b-robot manipulator
c-video display
Fig. 6. ZEUS surgical system; elements of Zeus robotic surgical system
The Zeus system is designed to provide the following benefits: • small cuts on the body, approximately the diameter of a pencil, • significantly reduced patient pain and trauma in cases of minimal invasive operations,
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shorter hospital stays and recovery time in cases of minimal invasive operations, applicable to beating heart and non-beating heart approaches, improved surgical precision and skill, improved visualization in 2D and 3D fields, and minimal surgeon fatigue with an ergonomic operating environment.
The system is designed for minimally invasive microsurgical procedures such as endoscopic coronary artery bypass grafting E-CABG. The Zeus surgical system has already been used in cardiac, gynecological, urological, general surgical and pediatric surgical procedures. In addition to these two surgical systems, the following surgical systems have also been developed: AESOP surgical robotic system and NeuroArm surgical robotic system. Service robots in remote treatment The innovation of the robot, called the Remote Presence-7 (RP 7) robot, marked an improved and higher quality form of distance communication. The RP-7 robot was manufactured by the private company InTouch Health located in Santa Barbara, California. The company (founded in January 2002) develops, manufactures and sells Remote Presence technology. Remote Presence (RP) is the ability to project oneself onto another location (without leaving your current location) and the ability to see, hear, and talk as if we are actually there. This robot has a size that can be compared to the size of a human being and allows an individual, as has been said, to project from one location to another so that he can see, hear and talk, while remaining at his current location. Remote Presence is a new modality for physician-patient interaction. Wherever access to medical expertise is limited, Remote Presence can effectively extend a physician’s ability to provide care to patients [8, 30]. The system operates on a “many-to-many” system architecture (Fig. 7), allowing the physician to connect from an office, hospital, or home to a robot located in the patient’s intensive care unit or hospital room to communicate with patients or patients’ families, medical staff, etc. With this technology, medical expertise can be made available to the patient anytime and anywhere. There are three main components of Remote Presence technology applied to this type of robot: • RP 7 robot, • Control Station, • Remote Presence Connectivity Service. RP (Remote Presence) Connectivity Service is the basis of the infrastructure, providing reliable connectivity between the robot and the control station [8, 31–33]. It delivers continuous monitoring of each robot, enabling immediate quality control and maximum uptime. As shown in Fig. 8, the doctor specialistsees the patient on the screen and communicates with him. Using the joystick, the doctor controls and maneuvers the RP-7 robot, and examines the results using the display. The RP-7 robot is located at the patient so
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Fig. 7. “Many-to-many” system architecture
Fig. 8. Service robot RP-7 – examination and communication of the specialist with the patient via the robot [37]
that he can see the specialist who is examining him, and also communicating and giving instructions to the patient, the nurse or the doctor who is with the patient. Service robots for patient rehabilitation Rehabilitation robots assist disabled people in those activities that they cannot perform on their own or are involved in therapies for people with the aim of improving their physical or cognitive functions [41]. Areas of application of rehabilitation robots are generally divided into robot therapy and assistance. In addition, rehabilitation robots include prostheses (prosthetics), nerve stimulation and devices for monitoring people during daily activities. The following categories are distinguished: • robotic therapy for mobility (walking), • personal rehabilitation robots,
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• robotic therapy of the upper extremities, • smart protheses, and • social service robots for personal care, autism and care for the elderly. Returning mobility to the patient is a particularly tedious and arduous job for therapists, and it is the primary target for automation [2, 25, 31]. Many mobile robotic training systems are already in use for therapy in several hospitals around the world, and many are still in the research phase. Due to limited space, we will show only a part of the robotic systems that are used today for the rehabilitation of patients. The AutoAmbulator, developed by HealthSouth Corporation (USA), consists of two-handed robots that help patients stand and distribute their body weight as needed. The interface for the patient’s legs is secured via straps on the thigh and ankle [2, 32, 33, 37] (Slika 9.a).
a)
b)
c)
Fig. 9. Service robot for rehabilitation: a-AutoAmbulator, b- HAL (Hybrid Auxiliary Limbs), c-The Next Generation Exoskeleton for Neurorehabilitation ExoNR [34, 36]
HAL (Hybrid Auxiliary Limbs) is a series of robots developed by Professor Sankai at Tsukuba University (Japan) and marketed by Cyberdyne (Japan). The exoskeleton was developed to increase the patient’s existing strength by a factor between 2 and 10. (Fig. 9 b). The Next Generation Exoskeleton for Neurorehabilitation Ekso Bionics unveiled EksoNR (Fig. 9 c), the next generation EksoGT— the most clinically used robotic exoskeleton. Developed for neurorehabilitation, EksoNR is an intuitive exoskeleton device that empowers patients recovering from stroke or other conditions to learn to walk again with a more natural gait. The device now includes new features and software enhancements to help physical therapists and patients get even more out of each rehabilitation session. In addition to the aforementioned service robots for patient rehabilitation, many robotic systems have been developed and used to help patients with impaired motor functions to recover and heal. Likewise, many robotic systems have been developed, and some are already in use, to help move and perform certain tasks for those patients where certain motor functions cannot be restored. We will name just a few: LokomatHocomais a robotic exoskeleton for rehabilitation, GT-I mobile trainer, ReWalk motorized quasirobotic system, robotic arm for rehabilitation after stroke, robotic wheelchair of various constructions, artificial pneumatic muscles, sensitive prostheses, etc.
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Service robots for disinfection It is well-known that disinfection is necessary and required in medical institutions – hospitals. We are currently witnessing a pandemic produced by the Covid-19 virus, so service robots that perform disinfection are highly welcomed. A number of constructive solutions for robots for disinfection have been developed [38–40]. Figure 10 shows two constructions such as SmartDosage UV technology and PowerBoost technology IRIS 3200 m.
Fig. 10. Service robots for disinfection
We have large amounts of antibiotics in hospitals that can become a source of some of the toughest antibiotic-resistant bacteria. That is why it is so important that hospital rooms are clean. It is known that cleaning in hospitals is performed by people who are prone to mistakes, which is why service robots should be used for disinfection [42]. Modern disinfection robots are autonomous. When programmed, they go to an empty room where patients stayed, and expose the empty room with strong UV rays for a few minutes until no microorganism remains alive, i.e. until disinfection is complete.
4 Artificial Intelligence in Medicine Artificial intelligence has already stepped into all aspects of healthcare, from online appointments, online registrations in medical centers, digitization of medical records, calls for reminders for further appointments and immunization dates for children and pregnant women to drug dosing, algorithms and warnings about adverse effects when prescribing combinations of several drugs [25]. The very idea of including computers to help diagnose and treat diseases has been present since the 1980s of the last century. We can graphically represent the application of artificial intelligence in the medical field, as shown in Fig. 11. As Fig. 11 shows, artificial intelligence finds application in: drug development, disease diagnostic, analysis of health plans, health monitoring, digital consultation, surgical treatment, managing medical data, personalized treatment, and medical treatment. It is expected that artificial intelligence will change medical practice in previously unknown
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Personalied treatmant
Managing medical data
Surgical treatment
Medical teratment
Drug development
Digital consultaƟon
Disease diagnosƟc
Analysis of healt plans
Health montoring
Fig. 11. Graphic representation of the application of artificial intelligence in the field of medicine
ways. However, many of its practical applications are still at the beginning and need to be better researched and developed. Healthcare professionals also need to get involved, understand and adapt to this progress in order to provide better health care to the patients. Artificial intelligence in healthcare is of great benefit for the diagnostic process. Misdiagnosis can be fatal [25, 27]. Scientists are working very intensively to significantly reduce the error rate by applying artificial intelligence, as shown in Fig. 12.
Fig. 12. Diagnostic process using artificial intelligence [27]
The development of information and communication technology has made it possible for doctors to store data on the disease (findings) of each patient and compare it with the medical findings of other patients. Scientists around the world are exploring how to use artificial intelligence to analyze large amounts of medical findings and find a pattern that could lead to new discoveries in medicine to improve individual diagnostics. It is also believed that artificial intelligence could help solve the problems caused by labor shortages (more than five million doctors are missing in the world; more than half of humanity does not have access to basic medical services), which could help institutions to become more efficient and ready to respond to modern medicine. The application of artificial intelligence in health care will improve and reduce the cost of health care, an illustration of which is given in the following example. Londonbased Babylon Health Company, assisted by its own artificial intelligence system and
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doctors from 50 countries all over the world, offers medical services such as personalized health assessments, counseling on health treatment and consultation with a doctor to its subscribers (according to data from August 2017, there are one million worldwide) at any time of the day or night, for just 50 British pounds a year (55 EUR). It is known that each individual responds differently to treatment and it would be best to adjust therapeutic procedures to each patient. This used to be impossible for implementation until the advent of high-speed computers and applications that developed algorithms which could perform all operations in the shortest time by analyzing and comparing all available patient data at high speed. IBM supercomputer Watson is already in use at 16 cancer institutes in the USA to serve as a sample analysis and to suggest diagnosis and treatment of patients. IBM recently acquired Merge Healthcare Company because of a database of 30 billion medical images for analysis and use, and the Watson supercomputer will soon be able to use analyses and predictions from those medical images for the needs of others. The possibilities of the analyses are limitless and could replace the radiologist. Another example of the application of artificial intelligence is a smartphone application powered by artificial intelligence that can solve the task of triage for 1.2 million people in north London in case of accidents and emergencies. In addition, these systems can learn from each individual case and can be exposed within minutes, in more cases than a doctor could see in several working lives. That is why the artificial intelligence-driven application is able to surpass dermatologists in the correct classification of suspicious skin lesions or why artificial intelligence is entrusted with tasks in which experts often disagree, such as identifying pulmonary tuberculosis on chest radiographs. An outstanding example is when the British artificial intelligence company DeepMind (owned by Google since 2014) with the Moorfields Eye Clinic and researchers from the University of London developed an artificially intelligent system that managed to properly refer patients with 50 different diseases with 94 percent accuracy, which is either equal to or better than the world’s specialists in eye treatment. An equally positive example is when IBM’s artificial intelligence system Watson in 2016 correctly diagnosed a woman in Japan with a type of leukemia after doctors failed to do so. Watson came to the diagnosis by comparing her chart with 20 million oncology findings in just a few minutes. One example of the use of artificial intelligence is in diagnosing breast cancer for women. Mammogram results are reviewed by two independent doctors, but from time to time the diagnosis is not accurately made or someone is misdiagnosed with cancer. Inorder to find if this mistake can be avoided by using technology, Google Health researchers decided to apply artificial intelligence to recognize breast cancer of mammograms of women in the USA and the United Kingdom. Despite the fact that artificial intelligence knew nothing about the medical history of patients, artificial intelligence was just as good at recognizing cancer as doctors, and there was a reduction in the number of mistaken diagnoses. For example, for American women, artificial intelligence reduced the number of misdiagnosed cancers by 5.7%, while for patients in the United Kingdom, the decline was 1.2%. The findings were published in the journal Nature. Leading companies such as Pfizer, Sanofi and Genentech are already using or plan to use artificial intelligence to minimize the cost of developing a new drug, which, according to Nature, today stands at approximately 2.6 billion USD. The World Medical Innovation Forum
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(WMIF) predicts that artificial intelligence could eliminate the need for tissue sampling because human body scanning devices will be so accurate that doctors simply won’t have to confirm diagnoses with samples. One of the co-founders of IBM artificial intelligent computer system Watson, David Ferrucci believes that artificial intelligence will primarily help us make better decisions. “Computers will give us a broader perspective, and we will have better, so to speak, peripheral vision. It will not allow us to miss something, and at the same time it will allow us to examine more possible outcomes of a certain situation”.
5 Robotics and Artificial Intelligence Artificial intelligence has continued to overcome many challenges in the recent years (less than ten years). Advances in new technologies such as mechatronics, computer science, electronics, and new materials have contributed to the development of robotic technology by developing sophisticated sensorimotor functions that allow robots to constantly adapt to continuous environmental changes, so that robots are now easily integrated into the existing environment, even though integration into the environment has been tried many times before. The integration of robots into the environment can be divided into observation, planning and manipulation. The basic compliance between artificial intelligence and robots is the optimization of the level of robot autonomy through learning [43–46]. The degree of this integration is measured as the ability to predict the future in interaction with the environment or task planning. Robots can nowadays perform specialized autonomous tasks such as: driving vehicles, flying in natural and artificial environments, swimming, buying items or carrying loads on different terrains. Even though robotic systems are created to perform human-like tasks, it is still far away and remains unattainable for now. One of the important applications of artificial intelligence in robotics is the task of perception, which is important not only for planning but also for creating an artificial sense of self-awareness of robots that enables the ability to support robot interaction with other entities in the same environment. We most often refer to this discipline as social robotics, which consists of two major domains: cognitive robotics and human-robot interaction. The domain of cognitive robotics is focused on acquiring knowledge through experience-based perception and imitation, and autonomous learning capacity with the aim of imitating the human cognitive system that regulates the process of acquiring knowledge and understanding, through experience and sensation [49]. In today’s world, robotics and artificial intelligence are playing an increasingly important role in the economy, future growth, and prosperity. We need to be open and prepared for the changes that are brought to our society by robotics and artificial intelligence, as well as their impact on job structure and skills base shifts. How quickly robotics and artificial intelligence will be implemented in our environment depends on the engagement of all of us because we need to have a clear and factual view of the present and future development of robotics and artificial intelligence. We must emphasize that there are also fears of the impact of technology on our society, but such fears should not hinder the progress of both robotics and artificial intelligence. More effort is needed to assess the economic impact and understanding of how to maximize the benefits of technology while at the same time mitigate the harmful effects. We must also
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note that it is of great importance to work on legal, regulatory and ethical issues for the practical deployment and responsible innovation of robotics and artificial intelligence. Continuous financial investment and responsible investment in robotics and artificial intelligence is leading towards the era in which robotics and artificial intelligence will transform the future of our society – our lives, our environment and our economy.
6 Conclusion Robots have become an inseparable part of our lives. Robots can be found as companions for the elderly, assisting surgeons in medical operations, intervening in life-threatening environments, working in the fields of forestry, agriculture, mining, freight, construction and demolition, in military and police applications, exploring space and cleaning our homes. They are often recognized for their skill, advanced visualization technology, and mechanical resistance. The mentioned roles of service robots are just part of the roles they play today. They have the potential to change our economy, our health, our standard of living and the world we live in. One of the most important roles of service robots nowadays belongs to those used in the field of medicine. They can be found performing simple tasks such as delivering medicine, food or mail to hospitals, more complex tasks such as robotic systems used to position the endoscopic camera in operating rooms or even performing remote operations using suitable robotic systems enabled by their design and applied technology (Zeus and Da Vinci surgical system), to complex surgical systems that are very successfully used in performing extremely sensitive surgical procedures in areas of medicine, where precision is extremely necessary such as microsurgery (NeurArm). Robots assist doctors to achieve precision in operating rooms, performing safer, less invasive techniques, and have great abilities beyond humans that make performing surgical procedures easier. Some advantages of using robotic surgical systems in surgical procedures are reflected in the lack of shaking of robotic arms, i.e. the ability to eliminate it, improved tissue manipulation by the use of their joints, work from all angles, and increased range of motion provided by their instruments. They improve the depth perception by giving a three-dimensional vision of the surgical site, and have the ability to scale the movements of the surgeon’s hands into finer movements, thus giving accuracy when performing operations in narrow spaces. Robotic surgical systems have become a major feature in operating rooms, advancing the field of minimally invasive surgery. With improved high-tech remote surgery techniques, surgeons can effectively perform surgery on people around the world, especially in remote locations where the telerobot can thus ensure that the patient undergoes surgery without the patient having to travel to the doctor or doctor to patient. Surgical robotic systems mark the beginning of a potentially large wave of surgical applications of robotic technology. With the help of surgical robots, surgeons will be able to expand their healing abilities in places in the human body that are currently out of reach. The continuous development of robotic technology and new technologies promises huge benefits in treatment that cannot yet be imagined. We assume that the application of Artificial Intelligence in medicine will give the greatest contribution, as well as nano-robotics, so in a very short time we will be able to diagnose a sick person and give the best recommendation for therapy and treatment that leads to very fast healing. This method will revolutionize the current way of medical
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treatment. Robotics and artificial intelligence are playing an increasingly important role in the economy, future growth, and prosperity in today’s world. How quickly robotics and artificial intelligence will be implemented in our environment depends on the commitment of all of us because we must have a clear and factual view of the present and future development of robotics and artificial intelligence.
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Attitude Controller Design for Micro-satellites Marco Claudio De Simone1(B) , Giuseppe Ventura2 , Angelo Lorusso1 , and Domenico Guida1 1 Depatment of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132,
84084 Fisciano, Italy [email protected] 2 MEID4 Academic Spin-Off of the University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
Abstract. The increasing interest of private companies in the aerospace sector has produced a growth of space missions oriented to exploration and colonization. Among the various markets, miniature satellites turns out to be the fastest-growing one. This paper aims to evaluate the control torques needed to ensure the attitude control of a micro-satellite. The orbital mechanics and the motion equations are presented in the first part of the paper. Furthermore, the primary disturbance torques, which act on the satellite varying its attitude and the interaction between the satellite and Earth, will be considered. Thanks to a 3D Solidworks microsatellite model, several simulations have been conducted in the multibody simulator Simscape. The attitude controller considered for this activity is composed of four reaction wheels. By using a Lagrange multipliers optimization method, a controller based on a PID control system is designed. Such a procedure allows evaluating minimized control torques in order to guarantee several satellite attitudes. The results obtained prove that reaction wheels represent an excellent compromise between reliability and performance at low expense for micro-satellites. Keywords: Micro-satellite · Orbits · Attitude control · Reaction wheels · Multibody
1 Introduction Micro-satellites are a particular class of satellites weighing between 10 and 100 kg [1]. The micro-satellites’ field is continuously growing, and it is estimated to grow up from 900 million dollars in 2016 to 2,5 billion dollars in 2025 [2]. It is necessary to equip the satellite with a suitable control system to ensure attitude control. The control systems could be divided into two class, depending on how theymanageattitudecontrol [3]: • passive control systems, who use natural phenomena and do not use external energy for managing the system; • active control systems that are capable of injecting energy into a specific point of the system. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 21–31, 2021. https://doi.org/10.1007/978-3-030-75275-0_2
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Active control systems guarantee more stable and accurate maneuvers than passive ones. Reaction wheels are a particular active control system that allows obtaining the desired attitude by varying the satellite’s total angular moment. Suppose an external torque acts on the satellite, generating an increase of the satellite’s angular momentum. In that case, the momentum devices will balance it by rotating to produce an angular momentum equal and opposite to the first one. In a rection wheel control system, each wheel spins independently to turn the spacecraft and absorbs disturbance torques. Typically, an attitude control system uses at least three separate reaction wheels. This control system is advantageous because it ensures a very accurate attitude control (order of magnitude of about 0.001°) and fast maneuvers [4]. Furthermore, this system does not depend on the orbit’s type and altitude because electric motors provide control torque. To evaluate the control torques required, to ensure attitude control for microsatellite, we developed a mathematical model of the problem [5] where the motion law’s equations were analyzed. Subsequently, we developed a satellite multibody model to carry out several dynamic simulations in Simulink [6]. The discussion of our results and our conclusions are reported in Sect. 3.
2 Materials and Methods In order to describe the satellite’s motion, we must first define the coordinate reference frame: • The inertial axis frame, the origin of which is at the center of the Earth. The z1 axis is in the direction of the north pole, the x1 axis is in the direction of the intersection between the equatorial plane and the Greenwich meridian, and the y1 axis is the cross product between the z1 axis and y1 axis; • The orbit reference frame, the origin of which is at the center of mass of the satellite. The zr axis points toward the center of the Earth’s mass and is also called the yaw axis. xr axis is in the orbit’s plane, perpendicular to the zr axis, in the direction of the satellite’s velocity. Such an axis is generally referred to as the roll axis [7]. The yr axis is normal to the local plane of the orbit and completes a three-axis right-hand orthogonal system. Such an axis is also called the pitch axis. ωr is the angular velocity of this frame relative to the inertial axis frame; • The satellite’s axis frame, the origin of which is at the center of the satellite’s mass, andthe axis xb , yb , zb correspond to the satellite’s principal axes of inertia. ωbr = pi + qj + rk is theangular velocity of this frame relative to the orbit reference frame. When ωri is expressed in thebody frame, it takes the form ωri,b . The angular velocity of the body relative to the inertial axisframe becomes: ωbi + ωbr + ωri,b
(1)
To evaluate the satellite’s attitude, we can use Euler’s angle: the roll, pitch, and yaw angles can be used to define the transition between the body axis frame and the orbit reference frame. The roll angle, φ, describes rotations around xb axis, the pitch angle, θ , describes spins around yb axis, and the yaw angle, ψ, describes turns around zb axis.
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With the ψ − θ − φ transformation, it is possible to link the body reference frame and the orbit referenceframe. Running these rotations in sequence, we obtain the A321 = Aψθφ transform matrix: ⎡
⎤ cos θ cos ψ cos θ sin ψ − sin θ ⎢ ⎥ Aψθϕ = ⎣ − cos φ sin ψ + sin φ sin θ cos ψ cos φ cos ψ + sin φ sin θ sin ψ sin φ cos θ ⎦ sin φ sin ψ + cos ψ sin θ cos φ − sin θ cos ψ + cos φ sin θ sin ψ cos φ cos θ
2.1 Analysis of the Angular Velocities For a circular orbit ωri , the orbit reference frame’s angular velocity relative to the inertial reference, is equal to ω0 = Rμ3 and it’s also called rate of frequency. The μ constant derives from the product between the gravitational constant, G = 6.67 ∗ 10−11
Nm2 , kg2
and the Earth’s mass M = 5.972 ∗ 1024 kg [8]. For small Euler angles, we have: ⎡
⎤ ⎡ ⎤ ⎤ ⎡ ⎤⎡ ωri,bx 1 ψ −θ −ψω0 0 ⎣ ωri,by ⎦ = ⎣ −ψ 1 φ ⎦⎣ −ω0 ⎦ = ⎣ −ω0 ⎦ 0 φω0 θ −φ 1 ωri,bz From (1), if ωri,b is known, it is possible to obtain the body angular velocity relative to the inertialreference [9]. In order to simplify the notation, set ω = ωri,b : ⎡
⎤ ⎡ ⎤ ⎡ ⎤ ωx p −ψω0 ⎣ ωy ⎦ = ⎣ q ⎦ + ⎣ −ω0 ⎦ ωz φω0 r
(2)
By considering the Euler’s transformation matrix, ωbr will be: ⎡ ⎤ ⎡ ⎤ p φ − ψ sin θ ⎣ q ⎦ = ⎣ θ˙ cos φ + ψ˙ sin φ ⎦ r ψ˙ cos θ cos φ − θ˙ sin φ For small angles, it is equal to: ⎡ ⎤ ⎡ ⎤ p φ˙ ⎣ q ⎦ ≈ ⎣ θ˙ ⎦ ψ˙ r According to this approximation, (2) can be rewritten as: ⎤ ⎡ ⎤ φ˙ − ψω0 ωx ⎣ ωy ⎦ = ⎣ θ˙ − ω0 ⎦ ωz ψ˙ + φω0 ⎡
(3)
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Finally, the angular acceleration vector can be written in the following way: ⎤ ⎡ ⎤ ⎡¨ ˙ 0 φ − ψω ω˙ x ⎥ ⎣ ω˙ y ⎦ = ⎢ ⎣ θ¨ − ω0 ⎦ ˙ 0 ω˙ z ψ¨˙ + φω
(4)
2.2 Motion’s Equations If we consider the satellite as a material point, the only force acting on it is the gravitational force: Fg = mg =
mMT G r2
This force tends to generate a uniform circular motion. The satellite will be on a stable orbit when the gravitational force is equal to the centrifugal force: Fc =
mv2 r
For pursuing a fixed distance from Earth, it is necessary to set the satellite on an orbit with a specific tangential velocity equals to: GMT v= r The satellite, in this paper, is modeled as a rigid body. So it is necessary to add more equations to our model. According to Euler’s moment equation, the external torques acting on the satellite are equal to the derivative of the total angular momentum of it, evaluated on an inertial reference, h˙ i . Following the body reference frame, Euler’s law can be written as: T = h˙ i = h˙ b + ωbi × h where h = Iω is the product between the satellite’s inertial matrix and his angular velocity. We can divide the external torque in control torque, Tc , and disturbance torque, Td , while the satellite’s total angular momentum is composed of the sum between the satellite’s angular momentum and the control system’s angular momentum: Htot = Hsat + Hdisp Considering these definitions, we obtain:
⎤
⎡ h˙ x + h˙ x,disp + ωy hz − ωz hy + ωy hz,disp − ωz hy,disp T = T c + T d = ⎣ h˙ y + h˙ y,disp + (ωz hx − ωx hz ) + ωz hx,disp − ωx hz,disp ⎦
h˙ z + h˙ z,disp + ωx hy − ωy hx + ωx hy,disp − ωy hx,disp
(5)
Attitude Controller Design for Micro-satellites
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2.2.1 Gravity Gradient Torque One of the most critical disturbance torque is the gravity gradient torque, particularly relevant in a circular orbit. The gravitational force’s action on the satellite can produce a torque that aligns the satellite’s body reference frame to the orbit reference frame [10]. It is possible to suppose the Earth as a perfect sphere with radially symmetric mass distribution. Setting R as the position vector from the Earth center to the center of mass of the satellite and ρ the position vector from the satellite’s mass center to the mass element, the attractive force acting on a single mass element is equal to: d F = −μ ∗ dm ∗
r r3
where r = R + ρ is the vector from the Earth center to the elementary mass [11]. This force produces an elementary torque around the center of mass of the satellite: d T g = −ρ × μ ∗ dm ∗
r μ ∗ dm =− ∗ρ×R r3 r3
(6)
Since ρ R, we can approximate:
1 1 R·ρ ≈ 1 − 3 R2 r3 R3
(7)
where R is the norm of the R vector. If we express this vector using the A Euler angle transformation, we will obtain: Rxb = R sin θ Ryb = −R cos θ sin φ Rzb = −R cos θ cos φ
(8)
Adding (6) to (7), we get: Tg =
3μ ∫ R · ρ ρ × R dm 5 R M
The components along the body axes of the gravity torque could be obtained by integrating and considering the (8), so we will obtain: 3μ
2 Tgx = 2R 3 Iz − Iy sin(2φ) cos (θ ) 3μ Tgy = 2R3 (Iz − Ix ) sin(2θ ) cos(φ) 3μ
Tgz = 2R 3 Ix − Iy sin(2θ) sin φ Such components are null in two particular circumstances: in the first one, the satellite’s inertia tensor is identical (for example, in the case of cubes and spheres); in the second one, the orbit reference frame and the body reference frame are aligned. In particular, in the latter case, one of the body reference frame axes will always be coincident with the R vector [12].
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For the specific case of a satellite around a circular orbit and a small Euler’s angle, the previous equations could be linearized; we will obtain:
Tgx = 3ω02 Iz − Iy φ (9) Tgy = 3ω02 (Iz − Ix )θ Tgz = 0 This torque will be a disturbance torque if our satellite’s attitude requires nonzero Euler angles. According to (3), (4), (5), (9) and considering that in our case, the products of inertia are null because thebody reference frame has an identical inertia matrix [13]. The control system is composed of four reactionwheels (that do not have an initial velocity). In this case, the motion’s law equations are the following:
Tdx + Tcx = Ix φ¨ + 4ω02 Iy − Iz φ + ω0 Iy − Iz − Ix ψ˙ + h˙ x,RW − ω0 hz,RW Tdy + Tcz = Iy θ¨ + 3ω02 (Ix − Iz)θ + h˙ y,RW
Tdz + Tcz = Iz ψ¨ + ω02 Iy − Ix ψ + ω0 Iz + Ix − Iy φ˙ + h˙ z,RW + ω0 hx,RW
2.3 Reaction Wheels Control System Reaction wheels can generate control torque by varying their velocity. The control system considered, is composed of four reaction wheels. Only three reaction wheels are necessary to guarantee and ensure attitude control. In this case, four of them have been used to provide further reliability to the system: if one of the wheels breaks down, the systems will continue to work [14].
Fig. 1. Reaction wheels arranged in a pyramidal configuration
We arranged the reaction wheels in a pyramidal configuration, as depicted in Fig. 1, and they are inclined to the pyramid’s base by the angle β, called tilt angle. Because of this inclination, each wheel can apply torques in the zB direction too. The torques delivered by the wheels are called Ti (i = 1, . . . , 4), while the torques produced along the three body axes are:Tˆ cx , Tˆ cy , Tˆ cz . These torques are linked to a specific matrix, Aw : ⎡ ⎤ T1 ⎤ ⎡ Tcx ⎤ ⎡ ˆ Tcx 1 0 −1 0 ⎢ cos β T2 Tcy ⎥ ⎣ Tˆ cy ⎦ = ⎢ ⎣ cos β ⎦ = ⎣ 0 1 0 −1 ⎦⎢ ⎣ T3 Tcz 11 1 1 Tˆ cz sin β T4 ⎡
⎤ ⎥ ⎥ ⎦
Attitude Controller Design for Micro-satellites
27
Unfortunately, this matrix cannot be inverted: if we know the principal axis’s control torque, we cannot derive each single reaction wheel torque. To overcome this problem, we must use the Lagrange’s optimization method: for this application the norm of the vector is minimized:
T T = T1 T2 T3 T4 Defined the Hamiltonian as H = are defined as follows:
4
2 i=1 Ti ,
and from Aw matrix, the control torques
Tcx = T1 − T3 Tcy = T2 − T4 Tcz = T1 + T2 + T3 + T4 By establishing the functions: g1 = T1 − T3 − Tcx g2 = T2 − T4 − Tcy g3 = T1 + T2 + T3 + T4 − Tcz the Lagrangian will be: L = H + λ1 g1 + λ2 g2 + λ3 g3 + λ4 g4 Moreover, the conditions for minimizing H will be: ∂L ∂T1 ∂L ∂T2 ∂L ∂T3 ∂L ∂T4
= 2T1 + λ1 + λ3 = 0 = 2T2 + λ2 + λ3 = 0 = 2T3 − λ1 + λ3 = 0 = 2T4 − λ2 + λ3 = 0
From the previous equations, we derive the final condition: T = T1 − T2 + T3 − T4 = 0
Adding this last equation to Aw matrix, we obtain the Aw that is squared, so the inverse is easy to be found: ⎡
⎡ ⎤ ⎤⎡ T1 1 0 −1/2 1/2 Tcx ⎢ T2 ⎥ 1 ⎢ 0 1 1/2 −1/2 ⎥⎢ Tcy ⎢ ⎥= ⎢ ⎥⎢ ⎣ T3 ⎦ 2 ⎣ −1 0 1/2 1/2 ⎦⎣ Tcz T4 0 0 −1 1/2 −1/2
⎤ ⎥ ⎥ ⎦
(10)
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2.4 Satellite Design In order to simulate the satellite’s motion, a 3D Solidworks model allowed to develop a rigid multibody model for the multidomain simulation environment SimScape. The model is reported in Fig. 2(a) and it is composed of two parts: the body and the control system (see Fig. 2(b) for detail). At the opposite ends of the body, there are two supports for extensible solar panels and four orientable thrusters. When designing a reaction wheel, the most significant limitation is its volume. For this reason, a high-density material has been chosen. Figure 2(b) shows the reaction wheel with a maximum diameter of 60 mm, and its inertial momentum is equal to 3.94 ∗ 10−4 kgm2 . The pyramidal structure has a square base, each side measuring 115 mm.
(a)
(b)
Fig. 2. Solidworks satellite model and detail of Reaction wheel
The Simulink model is composed of two parts. In the first part, as depicted in Fig. 3, the satellite’s model, the Earth model are linked by different frames connected by Rigid Transforms and a 6-DOF (Degree Of Freedom) joint. The bodies are linked by a inverse square law force block each other in order to simulate the gravitational field effects. The satellite’s initial altitude is equal to 756 km, its initial velocity, tangent to the orbit, is equal to v = 7476 m/s, and its initial angular velocity equals to ω = 0.0011 rad/sec. As aspected, the tangent orbit velocity and the distance from the Earth could be considered constant. The pitch, roll, and yaw angle will remain null: the body reference frame will always coincide with the orbit reference frame. The gravitational gradient torque is automatically computed in Simulink; in fact, if the satellite is placed with nonzero angles, the model will rotate around its center of mass [15]. On the right part of the Simulink model, reported in Fig. 3, there is the control system. Such controller is composed of three PD controller subsystem linked to a specific subsystem that includes the matrix from Eq. 10. Saturation blocks allow to simulate the maximum payable electric motor’s torque (about 0.5 Nm). The control system based on a PD logic is shown below: Tp = Kp e(t) Td = Kd e˙ (t) where Kp = 5 N/m and Kd = 10 Ns/m, are the proportional and derivative controller constants (they are the same for each axis), instead e(t) = anglerif − angle is the error between thereference angle and the Euler’s angle. Such angles describe the angularposition of the satellite’s axis frame respect to the orbit reference frame.
Attitude Controller Design for Micro-satellites
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Fig. 3. Simulink satellite multibody model with the control system
Several simulations were conducted in the Simscape environment in order to test the robustness of the attitude controller by using initial conditions and for various angular references. In order to emulate the aerodynamic resistance, a damping rotation coefficient b = 3 ∗ 10−4 Nm s/deg [16]. The satellite’s attitude controller is activated after 30 min. For every simulation the satellite velocity and altitude does not change. The torques that each reaction wheel must provide are evaluted for every case study.
(a)
(b)
Fig. 4. Rotational reference signals and optimal control torques in Simscape environment
In Fig. 4 is reported of the several simulations conducted, with initial one ◦ ◦ ◦ condition: φ0 θ0 ψ0 = 0 0 0 . Figure 4(a) shows the satellite attitude after the control system’s activation. The satellite’s attitude is changed after 200 s and each target ◦ angle is equal to 30 . The torques that each reaction wheel should provide to guarantee the attitude required are shown in Fig. 4(b).
3 Results and Conclusions The simulations have highlighted several noteworthy results. For micro-satellites, a control system composed of four reaction wheels is valid solution for controlling the behaviour of a satellite: it guarantees the attitude required in a shorter time than mechanical orbital’s time, using limited control torque. The maximum value of the control torque never exceeds, in absolute value, the saturation valure fixed in 0.2 Nm: it could
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be obtained with many DC motors. By comparing the tested control system with a passive control system, it is easy to see that the first one does not depend on the orbit and ensures a perennial three-axis stabilization and a pointing direction, which can vary. The reaction wheels control system does not need to make all the satellite rotate compared to a spin control system or a dual-spin control system. Furthermore, the reaction wheels control system has a few advantages over the other momentum-control devices: it is more flexible than the momentum wheels control system. For this reason, it is indicated for satellites that have to vary their attitude quickly and frequently. Compared to the control-moment gyroscope, the reactions wheel does not present the risk of falling in singularities because the rotor of the first one is fixed, while the second one’s rotor is linked to a revolute joint. The speed is the only reason why the gyroscope could substitute the reaction wheel. However, an optimal reaction time of the wheels as resulted from the simulations highlights their efficiency. The results obtained show that the control system produced represents an excellent compromise between reliability, performance, and costs for controlling micro-satellites’ attitude.
References 1. Pergola, P.: Small satellite survey mission to the second Earth moon. Adv. Space Res. 52(9), 1622–1633 (2013). https://doi.org/10.1016/j.asr.2013.07.043 2. Smith, P.: Nanosats and cubesats: the next 5 years. Proc. Int. Astronaut. Congr. IAC 5, 3772– 3777 (2014) 3. Cardoso, D.N., Esteban, S., Raffo, G.V.: A robust optimal control approach in the weighted Sobolev space for underactuated mechanical systems. Automatica 125, 109474 (2021). https:// doi.org/10.1016/j.automatica.2020.109474 4. Alkomy, H., Shan, J.: Modeling and validation of reaction wheel micro-vibrations considering imbalances and bearing disturbances. J. Sound Vib. 492, 115766 (2021). https://doi.org/10. 1016/j.jsv.2020.115766 5. Jenson, E.L., Chen, X., Scheeres, D.J.: Optimal spacecraft guidance with asynchronous measurements and noisy impulsive controls. IEEE Control Syst. Lett. 5(5), 1813–1818 (2021). art. no. 9296326. https://doi.org/10.1109/LCSYS.2020.3045384 6. Murcia Piñeros, J.O., dos Santos, W.A., Prado, F.B.A.: Analysis of the orbit lifetime of CubeSats in low Earth orbits including periodic variation in drag due to attitude motion. Adv. Space Res. 67(2), 902–918 (2021). https://doi.org/10.1016/j.asr.2020.10.024 7. Crisp, N.H., Roberts, P.C.E., Livadiotti, S., Macario Rojas, A., Oiko, V.T.A., Edmondson, S., Haigh, S.J., Holmes, B.E.A., Sinpetru, L.A., Smith, K.L., Becedas, J., Domínguez, R.M., Sulliotti-Linner, V., Christensen, S., Nielsen, J., Bisgaard, M., Chan, Y.-A., Fasoulas, S., Herdrich, G H., Romano, F., Traub, C., Seminari, S., Villain, R.: In-orbit aerodynamic coefficient measurements using SOAR (Satellite for Orbital Aerodynamics Research). Acta Astronaut. 180, 85–99 (2021). https://doi.org/10.1016/j.actaastro.2020.12.024 8. Walsh, J., Berthoud, L., Allen, C.: Drag reduction through shape optimisation for satellites in very low earth orbit. Acta Astronaut. 179, 105–121 (2021). https://doi.org/10.1016/j.actaas tro.2020.09.018 9. Salleh, M.B., Suhadis, N.M.: Roll attitude maneuver of CMG-Based controlled small satellite with magnetic torque gimbal angle compensation system. In: SpaceOps 2016 Conference, AIAA, pp. 2016–2602 (2016). https://doi.org/10.2514/6.2016-2602 10. Celenta, G., De Simone, M.C.: Retrofitting techniques for agricultural machines. In: Lecture Notes in Networks and Systems, 128 LNNS, pp. 388–396 (2020). https://doi.org/10.1007/ 978-3-030-46817-0_44
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11. Hülako, H., Yakut, O.: Control of three-axis manipulator placed on heavy-duty pentapod robot. Simul. Model. Pract. Theory 108, 102264 (2021). https://doi.org/10.1016/j.simpat. 2020.102264 12. Vejlupek, J., Chalupa, J., Grepl, R.: Model based design of power HIL system for aerospace applications. In: Mechatronics 2013: Recent Technological and Scientific Advances, pp. 177– 184 (2014). https://doi.org/10.1007/978-3-319-02294-9_23 13. Li, T., Kou, Z., Wu, J., Yahya, W., Villecco, F.: Multipoint optimal minimum entropy deconvolution adjusted for automatic fault diagnosis of hoist bearing. Shock Vib. 2021, 6614633, (2021). https://doi.org/10.1155/2021/6614633 14. Pappalardo, C.M., Guida, D.: Dynamic analysis and control design of kinematically-driven multibody mechanical systems. Eng. Lett. 28(4), 1125–1144 (2020). art. no. EL_28_4_19 15. Manca, A.G., Pappalardo, C.M.: Topology optimization procedure of aircraft mechanical components based on computer-aided design, multibody dynamics, and finite element analysis. In: Lecture Notes in Mechanical Engineering, pp. 159–168 (2020). https://doi.org/10. 1007/978-3-030-50491-5_16 16. Sicilia, M., De Simone, M.C.: Development of an energy recovery device based on the dynamics of a semi-trailer. In: Lecture Notes in Mechanical Engineering, pp. 74–84 (2020). https:// doi.org/10.1007/978-3-030-50491-5_8
Improving the Accuracy of Microhardness Measurement of Nanoelectronic Elements by the Silicic Probes of Atomic-Force Microscopy, that is Modified by Carbon Coverage Maksym Bondarenko1 , Victor Antonyuk2(B) , Iuliia Bondarenko1 , Iryna Makarenko1 , and Sergii Vysloukh2 1 Cherkasy State Technological University, Cherkasy, Ukraine 2 National Technical University of Ukraine “Igor Sikorsky
Kyiv Polytechnic Institute”, Kyiv, Ukraine
ABSTRACT. Possibility of measuring of microhardness of different surfaces of elements of nanoelec-tronics by means of method of atomic-force microscopy is considered in the article. Possibility of application of silicic probes that is modified by carbon coverage is first shown, that allows to conduct complex researches of surfaces and ultrathin coverages. Dependence of measuring exactness is shown on the microhardness of the investigated material. The range of measuring of microhardness of elements of nanoelectronics is set by such probes. Measuring exactness is megascopic to 20–28%, which is a range from 100 MPa to 39 GPa. It extends the nomenclature of materials at determination of its microhardness by atomic-force microscopy. Keywords: Atomic-force microscopy · Microhardness · Nanoelectronics · Silicic probe · Accuracy
1 Introduction The nanoindentation method has become more and more popular in recent years due to a decreaseof components size and an increased interest in the mechanical characteristics of elements in the nanometric range [5]. The peculiarity of the manifestation of the mechanical properties of materials at the nanoscale is associated with the manifestation of size effects (the theory of W. Nixon and H. Gao), as well as the possible diversity of the material in phase composition at the nanoscale and a sharp elastic-plastic transition in single crystals of materials (especially metals) [7, 6]. At the same time, methods for measuring the microhardness and elastic properties of materials, as well as thin coatings along the depth of the nanoindentor imprint, are generally recognized in the materials science society. These methods are based on the analysis of the diagram of nanoindentor penetration into the sample (for example, the © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 32–37, 2021. https://doi.org/10.1007/978-3-030-75275-0_3
Improving the Accuracy of Microhardness Measurement
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methods proposed by W. Oliver, J. Farom [9] (using a pyramidal indenter); J. Field, M. Swain, A. Fisher-Crips [4] ( for spherical indenters). A significant number of methods for processing primary data based on the results of nanoindentation using the Berkovich indenter, developed in recent years, are based on the use of scanning probe microscopy (SPM) methods, which makes it possible to determine more than two dozen different mechanical characteristics of materials (microhardness, wear resistance, tribological properties, etc.). Thus, the use of methods for determining microhardness using SPM, namely [3]: microsclerometry, restoration of the “tensioncompression” curve of the probe when it is brought to the surface, restoration of the indenter unloading curve without obtaining an image of the imprint, and others greatly simplify the acquisition and processing of test results. However, this does not take into account the possible deviation of the indent from the shape of a regular triangle due to the formation of piles and/or the subsidence of the sample surface on the sides of the indent, which can distort the study results. The expediency of using the atomic force microscopy (AFM) method for studying the microhardness of dielectric surfaces lies in the similarity of the principle of operation of a nanohardness tester and an atomic force microscope, which allows them to be combined in one complex, thereby significantly expanding the capabilities of probe methods and making them one of the most popular methods of metrological research in nanotechnology. At the same time, the application of the atomic force microscopy method for nanoindentation is one of the most promising in the complex study of the mechanical properties of dielectric materials and thin coatings (less than 100 nm) on their surface [8]. With such a study, during scanning of the sample relief, selective local measurement of interfacial zones or inclusions of micro- and nanometric sizes in the sample surface in one scanning cycle is possible [9]. However, the main problem of the active application of this approach to study the mechanical characteristics of dielectric materials is the need for the correct choice of a probe for AFM. Typically, a silicon probe is used for scanning a sample, and a diamond probe is used for nanoindentation. None of them are suitable for scanning and indentation in one cycle, since a silicon probe is too fragile for nanoindentation, and the use of a diamond probe for scanning dielectric materials is not rational due to its high cost and high hardness, which leads to the destruction of soft samples and, as a result, to distortion of scan results. The most promising approach to solve this problem is the modification of the surfaces of conical silicon probes with a carbon functional coating used to scan solid materials in the contact mode. In this case, an effective method for obtaining such coatings is the method of thermal evaporation in vacuum, the deposition technology of which is described in the author’s work [1]. The purpose of this work is to determine the accuracy of microhardness measurement by the AFM method using silicon probes modified with a carbon coating by comparing these results with the data obtained by the certified Vickers microdentation method.
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2 Experimental Procedure Tests of the microhardness of dielectric surfaces were made using an NT-206 atomic force microscope (Mikrotestmashiny, Belarus). The main tool in the research was silicon conical probes (tip radius of 8 nm) of the CSC18 brand (NT-MDT, Russia), modified with a thin carbon coating (Fig. 1).
a.
b.
c.
Fig. 1. External view of the console (a), diagram of the sensitive element of an atomic force microscope (b) and micrograph of the tip of the CSC18 probe (NT-MDT, Russia) (c), modified with a thin carbon coating
Modification is based on the formation of ultrathin (up to 10 nm thick) carbon coatings obtained by thermal deposition in vacuum (5…6). 10–3 Pa according to the method described in [1]. Previous studies held in [2] showed high strength, hardness and wear resistance of such coatings. Nanoindentation of the surfaces of the sample materials with a silicon conical probe modified with a thin carbon coating using the AFM method is used in the following sequence. The sample is scanned to select the nanoindentation site (nanoindentation site in a clean, homogeneous area, without inclusions and abrupt relief changes). The process of nanoindentation of the surface is carried out in the selected place of the investigated surface of the coatings (thickness 20 nm) under a gradually increasing load and under the following modes: for SiO2 coating - at a maximum load of up to 0.8 mN in 5 s; for HfO2 coating - at a maximum load of up to 0.6 mN in 7 s; for Au coating - at a maximum load of up to 0.5 mN in 7 s. From the unloading curve of the indenter - a silicon conical probe (the general view of the curve is shown in Fig. 2), the projection area of the indent under the maximum load is determined when the probe penetrates the surface using the following formulas: – when the probe is introduced to a depth of h ≤ 10 nm: Ac = π · r · hc
(1)
– when the probe is introduced to a depth of h > 10 nm: Ac =
π · (r1 + r) · (hc − r) + π · r2 cos ϕ
(2)
Improving the Accuracy of Microhardness Measurement
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where r is the radius of the tip of the probe; hc - indentation depth under maximum load; r 1 is the radius of the probe base; r1 = hc · tgϕ; ϕ is the slope angle of the tip of the conical probe (for probes CSC18: ϕ = 25°).
Fig. 2. General view of the curves of loading and unloading of the probe - nanoindenter: F max maximum load of the probe on the surface; hf - distance in height from the point of penetration of the probe into the surface to the point of its retraction
Further, substituting the value of r 1 into the formula (2): Ac =
π · (hc · tgϕ + r) · (hc − r) + π · r2 cos ϕ
or, after simplification (cos ϕ = 0,906; tg ϕ = 0,466): Ac ≈ 1, 1 · π · (0, 466 · hc + r) · (hc − r) + π · r 2
(3)
Calculate the microhardness of the sample material under study: H=
Fmax , Ac
(4)
where F max is the maximum probe load on the surface; Ac is the projection area of the probe imprint on the surface of the material under study. The accuracy of the results obtained is determined by comparing the data with the certified Vickers microindentation method using a diamond pyramid on the device DuroScan-10/20.
3 Discussion of the Experimental Results As a result of the experiments conducted to measure the microhardness by atomic force microscopy for various materials, which have found application in nanoelectronics and
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Fig. 3. .Dependences of the deviation of the microhardness of thin coatings on a silicon substrate on the depth of penetration of the nanoindenter into the surface: 1. X - for a probe modified with a carbon coating; 2. X - for unmodified silicon probe.
their further comparison with the certified Vickers microindentation method, the dependences of the accuracy of determining the microhardness of various materials for modified and unmodified AFM probes on the depth of probe penetration into the investigated surface, Fig. 3. ◯, 1 - respectively, obtained experimentally and approximated data for SiO2 coating; ●, 2 - respectively, obtained experimentally and approximated data for HfO2 coating; , 3 - respectively, obtained experimentally and approximated data for Au coating. As can be seen from the dependences shown in Fig. 3, with the increase in the penetration depth of the unmodified silicon probe, the deviation of the microhardness of thin coatings increases from the initial value of 1.00 to 1.063 (which corresponds to +6.3% deviation of the microhardness measurement accuracy) for the Au surface according to an exponential law, as well as for the results obtained for probes modified with a carbon coating (the maximum value of 1.03 (deviation of microhardness measurement accuracy by 3%) corresponds to SiO2 coating). At the same time, the accuracy of measuring the microhardness for SiO2 , HfO2 coatings using unmodified probes is only reduced to values of the nanoindentor penetration depth into their surface of 5 nm. This is due to the occurrence of critical mechanical loads, leading to the destruction of such a probe when it penetrates to a great depth. The limiting values when using the nanoindentation method in the study of dielectric surfaces with conical AFM probes modified with a thin carbon coating were calculated based on the load range of the order of 0.05–1.25 mN (for silicon probes 0.05–0.09 mN), which was applied to the probe in the process of measuring the microhardness, as well as the maximum penetration depth, which was about 60 nm (for a silicon probe 180 nm). Based on a formula (3), the range of microhardness measurements by probes modified with a thin carbon coating was obtained: 100 MPa–39 GPa, and for silicon probes: 477 MPa–11 GPa.
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4 Conclusion The deviation of the microhardness of thin coatings measured by the considered method of atomic force microscopy (NT-206) using CSC18 silicon probes modified with a carbon coating in comparison with the Vickers microindentation method on the DuroScan-10/20 device increases from 2.1% (for the coating surface Au) up to 3% (for SiO2 coatings) almost linearly. The range of microhardness measurements by silicon probes modified with a thin carbon coating is increased by 20–28% and amounts to 100 MPa–39 GPa, which makes it possible to expand the range of materials under study when determining their microhardness.
References 1. Antonyuk, V.S., Bilokin, S.O., Bondarenko, M.O., Bondarenko, Y., Kovalenko, Y.: Formation of wear-resistant coatings on silicon probes for atomic force microscopy by thermal vacuum evaporation. J. Superhard Mater. 37(2), 112–119 (2015) 2. Antonyuk, V.S., Bondarenko, Y.Y., Bilokin’, S.O., Andrienko, V.O., Bondarenko, M.O.: Research of microhardness of thin ceramic coatings formed by combined electron-beam method on dielectric materials. J. Nano Electron. Phys. 11(6), 06024-1–06024-5 (2019) 3. Charitidis, C.A., Dragatogiannis, D.A., Koumoulos, E., Perivoliotis, D.: Mechanical, Tribological Properties, and Surface Characteristics of Nanotextured Surfaces, in book: Nanomaterial Characterization. John Wiley & Sons, Athens (2016) 4. Fischer – Cripps A.C. : Nanoindentation. Springer-Verlag, New-York, USA (2002) 5. Karimzadeh, A.R., Koloor, S.S., Ayatollahi, M.R.: Assessment of nano-indentation method in mechanical characterization of heterogeneous nanocomposite materials using experimental and computational approaches. Sci. Rep. 9, 15763 (2019) 6. Liu, M., Lin, Jhe-yu, Cheng, L., Tieu, K., Zhou, K., Koseki, T.: Progress in indentation study of materials via both experimental and numerical methods. Crystals 7(10), 258 (2017) 7. Nix, W.D., Gao, H.: Indentation size effects in crystalline materials: a law for strain gradient plasticity. J. Mech. Phys. Solids 46(3), 411–425 (1998) 8. Notbohm, J., Poon, B., Ravichandran, G.: Analysis of nanoindentation of soft materials with an atomic force microscope. J. Mater. Res. 27(1), 229–237 (2011) 9. Oliver, W.C., Pharr, G.M.: An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7(6), 1564–1583 (1992)
An Experimental Study of the Influence of Mounting Errors on the Load Distribution Along the Face Width in a Spur Bevel Gear Viktor Ivanov1(B) , Svitlana Ivanova2 , Galyna Urum2 , and Dmytro Purich1 1 Odessa National Polytechnic University, Odesa, Ukraine
[email protected] 2 South Ukrainian National Pedagogical University named after K. D. Ushynsky,
Odesa, Ukraine
Abstract. The experiment was carried out on a setup that allows you to change the position of the bevel gear axes. Spur bevel gears were made of Plexiglas. The contact area along the face width of the teeth is determined based on optical measurements with a microscope. The load distribution along the face width based on the contact area of each tooth part is defined. The research was carried out in accordance with the theory of the design of experiments. The combination of mounting errors was set in accordance with the Hartley’s experiment plan for forth input factors. The dependence of the load distribution factor on mounting errors has been established. The method of transferring data obtained on Plexiglas models for steel gears is indicated. This method is based on the use of similarity theory. Keywords: Plexiglas gear model · Spur bevel gears · Mounting errors
1 Introduction Gear calculations using FEM are widespread. The result of these calculations is the maximum contact and bending stresses. Standard methods for calculating gears use other methods for determining stresses. An integral part of standard calculation methods is the determination of the load distribution factor kHβ .The calculation of the load distribution factor in spur bevel gears in ISO and AGMA standards is not accurate and requires further research [1]. Mounting errors have the greatest effect on the load distribution factor in spur bevel gears. To reduce the sensitivity of the spur bevel train to mounting errors, a crowning contact is usually used [2]. An experimental assessment of the influence of mounting errors on the load distribution factor in spur bevel gears without and with the use of crowning contact was performed in [3]. A comparative analysis of the influence of elastic deformations, thermal deformations, manufacturing and mounting errors was carried out using several software packages [4]. In the case of manufacturing bevel gears by plastic deformation, the role of manufacturing errors increases, especially for skew bevel gears [5]. For large-sized bevel gears, it is also relevant to take into account © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 38–45, 2021. https://doi.org/10.1007/978-3-030-75275-0_4
An Experimental Study of the Influence of Mounting Errors
39
manufacturing and mounting errors. The crowning contact profile for large-sized spur bevel gears is calculated. Taking into account this crowning profile, a three-dimensional model of gears was created, which was made using the CAM process. An experimental study of the shape of a tooth contact pattern was carried out using a coordinate measuring machine [6]. The most detailed study of mounting errors was carried out in [7]. Six types of mounting errors are considered: pinion offset, axial movement of pinion apex, displacement of the pinion along the gear axis, tooth spacing error, angular displacement of the driven gear member, horizontal angular misalignment of pinion axis, vertical angular misalignment of pinion axis. The tooth contact pattern in spiral bevel gears is determined taking into account all these six mounting errors. Another approach to determining the relative position of the wheels is proposed in [8]. Four types of mounting errors are considered: offset error, pinion distance error, wheel distance error and shaft angle error. The influence of the shaft angle error on the displacement of the initial contact point is considered in [9]. It has been shown that crowning contact in a spur bevel gear can be achieved through deliberately introduced mounting errors. This is possible if a deviation of the shaft angle adjusts to deviation of mounting distance, then initial contact can be in the middle of the face width. An interesting option is when the angle between the axes of the bevel gear is 0.2 … 0.3 degrees less than the right angle, which can make it possible to split the power flow in the bevel gear stage [10].
2 The Experimental Setup Design The experimental setup consists of a base plate 1 with carriages 6 located on it, the supports 2, in which the sleeve with shafts 4 and bevel wheels 7 are located (Fig. 1). The loading system consists of a lever 9, a dynamometer 3 and a jack 5. The torque on the shaft is transmitted through the key to the bevel wheel, the teeth of which interact with the pinion teeth. The stand is equipped with an orientation device 10, which provides six degrees of freedom of the microscope 11. The setup for static research allows to study bevel gears with various parameters of the gear mesh, the design of wheels, shafts and bearing unites, as well as errors in the relative position of the links. The dimensions of the bevel gear, which can be assembled on the setup are limited by the maximum outer cone distance Re = 880 mm and the maximum outside diameter of the wheel d ea = 630 mm. The setup allows assembling a bevel gear with a cantilever pinion, and the wheel can be either cantilever or located between the supports. The greatest distance between the supports is limited by the carriage length of 800 mm. Based on the analysis of the actual dimensions of the setup elements and methods for controlling the relative position of the links, the accuracy of measuring the mounting errors was determined. Offset error fa is set using shims installed under the supports. The offset error is calculated as the difference between the distances from the base plate to the surface of the wheel and pinion shafts. The accuracy with which the fa value was measured is found by the equation fa = δ2fl + δ2ms + δ2sh , (1)
40
V. Ivanov et al.
where δfl - is the base plate non-flatness value; δms - measurement error; δsh - error in determining the shaft diameter.
Fig. 1. The experimental setup design
Distance errors fAM 1 and fAM 2 were set by the displacement of the carriages and were measured with an indicator relative to the side surface of the carriages of a wheel and pinion, respectively. Distance error of a pinion fAM 1 was controlled by measuring the distance from the common reference surface of the pinion to the wheel shaft. This distance is the sum of the distance from the common reference surface to the inner end of the pinion loi and the distance from the inner end to the wheel shaft lpw . The measurement accuracy of the pinion distance error was determined by the formula (2) fAM1 = δ2oi + δ2pw + δ2sh , where δoi – is the mistake in measurement the distance from the common reference surface to the wheel shaft; δpw - is the mistake in measurement the distance from the inner end to the wheel shaft. The mistake in wheel distance error was controlled by measuring the mismatch of the common reference surfaces of the gear and wheel. Shaft angle error E was controlled by measuring the gap between the side of one carriage and a machinist square right angle ruler attached to the side surface of the other carriage. The gap was measured using two indicators spaced along the length of the machinist square. Measurement accuracy of a shaft angle error was determined by the formula (3) E = δϕ2car + δϕ2c−sp + δ2sp−sh + δ2sh ,
An Experimental Study of the Influence of Mounting Errors
41
where δϕcar - non-perpendicularity of a carriage; δϕc−s - non-parallelism of carriage and support; δϕsp−sh - non-parallelism of support and shaft. Calculations based on dependencies 1–3 showed that the given method of measuring errors allows ensuring the following accuracy of the gear assembly: f a = 12 mcm; f AM 1 = 16 mcm; f AM 2 = 18 mcm; E = 0,028°. The use of models of bevel gears made of Plexiglas makes it possible to use an optical method for studying the load distribution in the engagement. The load distribution was determined directly by measuring the dimensions of the contact area. The bevel pinion and wheel were made of 200 mm thick cast Plexiglas used for glazing fighters. This made it possible to manufacture gear models using mechanical processing, without the use of gluing. The mechanical characteristics of Plexiglas grade SO-120-A (GOST 10667-90) are as follows: modulus of elasticity E = 3000 MPa, allowable tensile stress 77.5 MPa, bending 105 MPa. Parameters of spur bevel gear: number of teeth of pinion 17 and wheel 30, modulus 10 mm, outer cone distance Re = 172.41 mm, face width b = 50 mm (Fig. 2).
Fig. 2. Plecsiglass gear wheel and gear pinion
The high value of the modulus was chosen for reasons of increasing the accuracy of optical measurements. The thickness of the tooth at the outer end (15.75 mm) is less than 20 mm. To avoid optical distortion for a given Plexiglas grade necessary that the deviation of the microscope optical axis does not exceed 8 min, when measuring the contact area width in one experiment. Determination of the contact area size was carried out in ten equal sections, which were marked on the tooth by lines drawn with a needle.
3 Experimental Study The experiment was carried out according to Hartley’s plan [11]. Its advantage is the close to the minimum generalized variance of all estimates of the model coefficients
42
V. Ivanov et al.
(D - optimality). Mounting errors are selected as variable factors fa , fAM 1 , fAM 2 and load F t . For four factors, the experiment planning matrix contains seventeen experiments. The following order of numbering of variable factors is accepted: fAMr1 sinδ1 − X1 , fAMr2 sinδ2 −X2 , far −X3 , FN −X4 . Factors X 1 , X 2 , X 3 are included in the three-letter interaction of the type X 1 X 2 X 3 = 1, as a result of which they are independent both from each other and from the coefficients of linear effects b1 , b2 , b3 and pair interactions b12 , b14 , b34 , b34 . There is a correlation between the coefficients b0 ,b11 ,b22 ,b33 ,b44 . In accordance with the assembly scheme of the bevel gear, the levels of variation of the factors were selected (Table 1). Table 1. Factors and variable levels of factors Factor level
Variable factors fAM 1 (mcm)
fAM 2 (mcm)
fa (mcm)
F N (N)
base level (X i = 0)
350
270
0
360
variation interval
350
270
200
180
upper level (X i = +1)
700
540
+200
540
lower level (X i = −1)
0
0
−00
180
In accordance with Hartley’s plan, experiment No. 17 was matched by baseline levels of all four factors. To determine the coefficient variance, experiment no. 17 was repeated 17 times. The variance of a series of 17 experiments was Sy = 0,0289. The other 16 experiments were not completely duplicated, only the measurement of the contact area was repeated three times after repeated application of the load. As a result of a series of experiments, the values of the load distribution factor in each of the K experiments were obtained, which are the response function yK (Table 2). Table 2. Experimental and calculated data of the load distribution factor Data type
Experiment number 1
2
3
4
5
6
7
8
9
Experimental
5,14
1,34
1,39
1,33
5,41
1,37
1,62
2,15
1,17
Calculated
5,15
1.38
1.36
1.15
5.39
1.35
1.63
2.34
1.78
Data type
Experiment number 10
11
12
13
14
15
16
17
Experimental
1,24
2,31
1,31
2,87
1,31
1,22
1,62
1,38
Calculated
1.27
2.28
1.27
2.90
1.21
1.22
1.64
1.44
Based on these data, the coefficients of the model were calculated according to the Hartley’s plan equations [11] (Table 3).
An Experimental Study of the Influence of Mounting Errors
43
Table 3. Coefficients of the model Coefficient designation
b0
b1
b2
b3
b4
b12
b13
Coefficient numerical value
1,44
0,264
0,506
0,847
−0,210
0,195
0,339
Coefficient designation
b23
b24
b34
b11
b22
b33
b44
Coefficient numerical value
0,649
0,160
−0,150
0,091
0,333
0,619
−0,110
The experimentally obtained model has the form y = b0 + b1 X1 + b2 X2 + b3 X3 + b4 X4 + b12 X1 X2 + b13 X1 X3 + b14 X1 X4 + b23 X2 X3 + b24 X2 X4 + b34 X3 X4 + b11 X12 + b22 X22 + b33 X32 + b44 X42 .
(4)
Using this formula, the values of the response function were found, which represent the load distribution factor at seventeen control points (Table 2). To check the adequacy of the resulting model, the Fisher criterion was used Ff2 f1 =
2 Sinad Sy2
(5)
2 where Sinad - is the variance of inadequacy. The variance is found by the formula [11]
N Sinad =
K=1 (yKmodel − yKexper )
f2
2
(6)
where yKmodel and yKexper the value of the response function in the K - th experiment, calculated by the model Eq. (4) and found experimentally, respectively; f 2 - the number of freedom degrees, defined as the difference of the number of experiments and the number 2 = 0.0030, then Ff2 f1 = 3.57, which of model coefficients. As a result of calculating Sinad is less than the tabular value of the Fisher criterion at a 5% level of dependence (F tabl = 3.68 if f 1 = 15 and f 2 = 2). Thus, the hypothesis about the adequacy of the model is not rejected. To check the significance of the coefficients in the regression equation, the variance of the coefficient estimates are calculated. Comparison of the t-criterion calculated values with the tabular t tabl = 2.13 (5% significance level at f1 = 15) shows that the coefficients of the regression equation are statistically significant. The results obtained for Plexiglas gears can be applied to steel gears using the coefficient of similarity. The stressed states of the object and the model are similar in the case of equality of dimensionless relations [12]. σm σo = , [σM ] [σP ]
(7)
44
V. Ivanov et al.
where σM ,σO , - stresses in the model and object, and [σm ],[σP ] - permissible stresses for metal and Plexiglas, respectively. In addition, for the equality of linear displacements scales to dimensions scale, the following ratio must be observed [12]. σO β = , σM α
(8)
where β = FO /FM -the ratio of the force in the object gearing FO, to the force FM, in the model gearing; α - is the ratio of the linear dimensions of the object lO and the model lM. In most cases, it is preferable that the displacements on the model were significantly greater than the displacements in real gear drives, since the value of the mounting errors can be increased by the same amount lO =
EM β lM , EO α
(9)
where EO and EM - elastic modules of the object and model, respectively. From formula (9) it can be seen that one model can be associated with several real gears with different coefficients α.
4 Conclusion It is very difficult to experimentally determine the contact stresses in a gearing, therefore indirect methods are used. Using models of Plexiglas gears allows directly measuring the width of the contact area and finding contact stresses. The study of the mounting errors influence on the load distribution factor is complicated by the fact that manufacturing errors of gears and assembly of the experimental setup can be commensurate with the mounting errors. Plexiglass models solved this problem, since several times the large elasticity deformation of Plexiglas allows several times to scale the mounting errors. The experimental methodology was based on Hartley’s four factorial plan, which includes interaction effects and quadratic effects. Dependence of load distribution factor on load in gearing, offset error, pinion distance error and wheel distance error is obtained. The dependences of the similarity theory are given, which allow using the data obtained on the models made of Plexiglas for steel gears.
References 1. Osakue, E.E., Anetor, L.: Comparing contact stress estimates of some straight bevel gears with ISO 10300 standards. In: ASME International Mechanical Engineering Congress and Exposition, vol. 52187, p. V013T05A025 (2018) 2. Xuemei, C., Jiajia, L.L., Zhanrong, M.: Sensitivity analysis of installation errors of the straight bevel gear modification tooth surface. J. Mech. Transm. 4(9), 40–43 (2014) 3. Cao, X.M., Sun, N., Dend, X.Z.: Design for straight bevel gear based on low installation error sensitivity and experiment tests. J. Aerosp. Power 31(1), 227–232 (2016) 4. Zhang, F., Tian, X., Cui, H.: The modification design of involute straight bevel gear. IERI Procedia 3, 52–59 (2012)
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5. Fuentes, A., Iserte, J.L., Gonzalez-Perez, I., Sanchez-Marin, F.T.: Computerized design of advanced straight and skew bevel gears produced by precision forging. Comput. Methods Appl. Mech. Eng. 200(29–32), 2363–2377 (2011) 6. Tsuji, L., Kawasaki, K., Gunbara, H., Houjoh, H., Matsumura, S.: Tooth contact analysis and manufacture on multitasking machine of large-sized straight bevel gears with equi-depth teeth. J. Mech. Des. 135(3), 034504 (2013) 7. Simon, V.: Influence of tooth errors and misalignments on tooth contact in spiral bevel gears. Mech. Mach. Theor. 43(10), 1253–1267 (2008) 8. GOST 1758-81 Basic norms of interchangeability. Bevel and hypoid gears. Tolerances 9. Ivanov, V., Urum, G., Ivanova, S.: Achieving crowning contact of spur bevel gears through deliberately introduced mounting errors. In: Karabegovi´c, I. (ed.) New Technologies, Development and Application III. NT 2020. Lecture Notes in Networks and Systems, vol. 128, pp. 89–97 (2020) 10. Ivanov, V., Urum, G., Ivanova, S., Naleva, G.: Analysis of matrix and graph models of transmissions for optimization their design. Eastern Euro. J. Enterp. Technol. 4(1), 11–17 (2017) 11. Hartley, H.: Smallest composite designs for quadratic response surface. Biometrics 15, 611– 624 (1959) 12. Sedov, L.I.: Similarity and dimensional methods in mechanics. CRC Press, Boca Raton (1993)
Numerical and Experimental Stress Analysis of a Thin-Walled Cylindrical Tank with a Flat Bottom Elmedin Mesic1 , Muamer Delic1(B) , Nedim Pervan1 , Adis J. Muminovic1 , and Vahidin Hadziabdic2 1 Department of Mechanical Design, Faculty of Mechanical Engineering,
University of Sarajevo, Sarajevo, Bosnia and Herzegovina [email protected] 2 Department of Mathematics and Physics, Faculty of Mechanical Engineering, University of Sarajevo, Sarajevo, Bosnia and Herzegovina
Abstract. Methodology for design of a thin-walled cylindrical thank with a flat bottom is presented in this paper. Except design, methodology for analytical, numerical and experimental analysis of stresses on the thank is also presented. After analytical calculations, geometrical modeling is carried out using CAD/CAM/CAE system CATIA. Distribution and values of principal strains and stresses are presented. Mathematical and numerical model is developed for linear elastic and isotropic material. In addition, introduction is given for theory of stresses for thin-walled thanks. For numerical structural analysis finite element method is used. Experimental stress analysis is carried out by tensometric measuring. Comparison of results from analytical, numerical and experimental analysis a predominantly good agreement with certain deviations can be found. Based on the comparison of the results obtained using analytical calculation, numerical method and experiment, a good match of the results can be observed. By comparing the results, the FEM model was verified. Keywords: Analytical calculations · Geometrical modeling · FEM analysis · Tensometric measurement
1 Introduction Thin-walled thanks belongs to most responsible and the most demanding welded products, primarily because they are dangerous for peoples, ecology and company. Most important aspect of this type of product are welded joints. For design process of this products it is necessary to be familiar with best technology for manufacturing of this type of products and to avoid unnecessary loses during manufacturing processes [1]. Thin-walled tanks have several main parts: shell, flat bottom, supports, nozzle and control equipment [2, 3]. Shell is the body of the tank and it is main components which support fluid pressure inside the tank. Shell is manufactured by welding of several parts together. All parts have ring shape and they have same axis [4, 5]. Most of the shells have © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 46–53, 2021. https://doi.org/10.1007/978-3-030-75275-0_5
Numerical and Experimental Stress Analysis
47
cylindrical, spherical or conical shape. Bottoms can be flat, convex or concave. Convex bottoms can be conical, torispherical, shallow, semi-ellipsoidal or hemispherical. Concave bottoms can be inversely conical of inversely bowl-shaped [6].
2 Analytical Calculations of Thin-Walled Tank with Flat Bootom In all types of tanks which are loaded with internal or external pressure stress appear in tank shell. Stress which appear in tank have three axis of influence, three principal stresses: 1. σm – meridional (longitudinal or axial stress) 2. σt – circular (peripheral or tangential stress) and 3. σr – radial stress Basic design parameters for calculation of tank are: – – – –
Pressure p = 0,47 MPa Tank diameter Dv = 141 mm Basic material X5 CrNiMo 18 10 Tank length L = 300 mm
In this study only shell of tank will be analyzed. Stress distribution and stress values will be determined using analytical, numerical (FEM) and experimental analysis. First step of analytical calculation is to calculate shell thickness δ according to the Eq. 1 [1]. δ=
Dv p 2 σSv ϕz +p
+ C1 + C2 + C3
(1)
Where: Dv – Outer diameter of tank shell, p - maximal allowed pressure, σv = 220 MPa – Yield strength of material X5 CrNiMo 18 10, S = 1, 5 – factor of safety, ϕz = 0, 8 – factor of fading of basic material, C1 = 0 – addition which take in consideration deviations of shell thickness of a tank, C2 = 1 – addition for corrosion, C3 = 0– addition for external pressure, Using Eq. 1 value for shell thickness is calculated: δ = 1, 28 mm Thickness of flat bottom of a tank can be calculated using equation [1]: s = C(D1 − d1 ) p σSv + C2
(2)
48
E. Mesic et al.
Where: C = 0, 35– analytical coefficient, D1 = 135 mm – analytical diameter, d1 = 0 – calculated diameter of anchoring, C2 = 0, 3 – addition for wear, Now using Eq. 2 bottom thickness can be calculated: s = 2, 97 mm adopt s = 3 mm This research includes manufacturing of real tank, because of that (easy manufacturing) bottom thickness and shell thickness is adopted as same with the value of 3 mm. 2.1 Analysis of Stress Distribution As earlier mentioned thin-walled thank have three types of loads: meridional, circular and radial. These stresses can be calculated using following equations [1] Table 1: Circular stress can be calculated using equation: σt =
di p 2δ
(3)
Meridional stress can be calculated using equation: σm =
di p 4δ
(4)
Where: di = 135mm – inner diameter of a tank, Radial stress can be calculated using equation: σr =
p 2
(5)
Table 1. Analytical results for principal stresses on the tank shell Type of stress
Value
Circular (σt )
10,57 MPa
Meridional (σm ) 5,29 MPa Radial (σr )
0,235 MPa
3 Geometrical Modeling and Fem Analysis Design process, in its basic, is information process which starts with an idea, use knowledge and data, and ends with information about how the product will look like and how it will behave in real exploitation [7, 8]. 3D geometrical modeling is done using CATIA
Numerical and Experimental Stress Analysis
49
Fig. 1. Final 3D geometrical model of a tank
system. Firstly, every part of a tank is modeled separately and then assembly is created. This assembly is used for FEM analysis. 3D model of a tank with flat bottom and with all elements like the real model is shown on Fig. 1. For FEM analysis only 3D model of tank will be used, without unnecessary parts like supports and connections. For FEM analysis basic tools from Generative Structural Analysis module of CATIA system was used. 3D geometrical model is meshed and constrains are applied. After that loads are applied in the form of internal pressure inside of the tank. Because of the symmetry which this types of models have, only 1/8 of a model is used for analysis. Modeling is done using Generative shape design module where 2D surface model of a tank was developed [9, 10]. For mesh element type, 2D triangular elements was used. FEM model prepared for analysis is shown on Fig. 2.
Fig. 2. FEM model of a tank
Figure 3 shows principal stresses with detail presentation of meridional and circular stress which are measured on the middle part of a tank shell. On the same middle part of the tank shell, experimental strain gauges will be applied. Values of stresses from numerical structural FEM analysis are shown in Table 2.
50
E. Mesic et al.
Fig. 3. Stress distribution on the tank
Table 2. Values from FEM analysis in the shell of a tank Stress type Value Circular
11,2 MPa
Meridional 5,04 MPa
4 Experimental Stress Analysis of Thin-Walled Tank For experimental stress analysis modern tensometric equipment from HBM was used. This equipment consists of DAQ system QUANTUM X MX840B, software Catman, strain gauge rosette of T type (Oznaka HBM) and linear strain gauge (Oznaka HBM). T type strain gauge rosette can measure stress in two directions. Compensation strain gauge is a linear strain gauge with the same characteristic of the measuring fiber [11, 12], (Fig. 4).
Fig. 4. Tensometric equipment
Active T rosette is applied at the middle part of tank shell and arranged in a way so it can measure circular and meridional stress. Compensation strain gauges is applied to the small part manufactured from the same material as the tank shell and it is used to compensate the temperature influences. One fiber T rosette and one compensation
Numerical and Experimental Stress Analysis
51
strain gauge are connected in half Wheatstone bridge [13, 14]. How they are arranged and connected is shown in Fig. 5.
Fig. 5. Arrangement and connection of strain gauges
Experimental analysis is done using whole system which will enable to achieve intended pressure. This system is consisted from water tank, pump to achieve pressure and rest of control equipment (automatic pressure regulator, safety valves, and valves to open or close the water flow). Pressure is increased continuously from 1 bar up to 4, 7 bar, which correspond to the pressure of 0,47 MPa which is used for analytical and numerical analysis. Diagram of pressure-strain is shown on Fig. 6.
Fig. 6. Diagram pressure – principal strain
Using measured strains and using Eqs. 6 and 7, principal stresses in circular (σ1 ) and meridional (σ2 ) directions can be calculated. Values are shown in Table 3. σ1 =
E (ε 1−μ2 1
+ με2 )
(6)
σ2 =
E (ε 1−μ2 2
+ με1 )
(7)
52
E. Mesic et al.
Where: ε1 - principal strain in circular direction ε2 - principal strain in meridional direction E = 193 GPa - modulus of elasticity μ = 0,29 – Poisson’s coefficient Table 3. Results of measured principal strains and calculated principal stresses Pressure, bar
Strain in circular direction, µm/m
Strain in meridional direction, µm/m
Circular stress, MPa
Meridional stress, MPa
1
6,79
1,59
1,52
0,74
2
10,92
4,4
2,57
1,59
3
19,37
8,28
4,58
2,92
4
38,36
13,24
8,44
5
4.7
49,50
19,5
11,62
7,13
Using equations for field stress analysis, values of circular and meridional principal stress on the tank shell are calculated. Results for all three types of analysis are shown in Table 4. Table 4. Principal stresses Analytical calculations
Numerical analysis
Experimental analysis
Circular, MPa
10,57
11,2
11,62
Meridional, MPa
5,29
5,04
7,13
5 Conclusion Methodology for analytical, numerical and experimental analysis of thin-walled tank is presented in this paper. Tank have shell and two flat bottoms. It is supported by two supports. Using design data from analytical calculation geometrical model is developed using CATIA system. During numerical structural FEM analysis tank is considered as surface model and it is meshed with 2D finite elements. Stress distribution showed that radial stress is significantly smaller in comparison to circular and meridional stress, because of that, radial stress can be ignored što je saglasno sa teorijom thin walled tank. Except analytical and numerical (FEM) analysis, experimental analysis is also carried out in the Laboratory for tensometric measurement. Using strain gauge, strains on the tank shell are measured in two perpendicular directions. From Table 4 it can be
Numerical and Experimental Stress Analysis
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seen that experimental analysis gives slightly different results in comparison to analytical calculations and numerical analysis. Reason for that is because of residual stresses from manufacturing process which exist inside material. Also this difference can occur because of small deviations of inside pressure.
References 1. Moos, D.R., Basic, M.M.: Pressure Vessel Design Manual, Elsevier Inc., 4th edn. (2012) 2. Naser, M.Q., Swami Gupta, A.V.: Structural and Thermal Analysis of Pressure Vessel by using Ansys. Int. Sci. Eng. Technol. Res.. 2(8), 740–744 (2013) 3. Siva Kumar, B., Prasanna, P., Sushma, J., Srikanth, K.P.: Stress analysis and design optimization of a pressure vessel using ansys package. Mater. Today Proc. 5(2), 4551–4562 (2018) 4. Wadkar, V.V., Malgave, S.S., Patil, D.D., Bhore, H.S., Gavade, P.P.: Design and analysis of pressure vessel using ansys. J. Mech. Eng. Technol. 3(2), 1–13 (2015) 5. Devaraju, A., Pazhanivel, K.: A study on stress analysis for design of pressure vessel. Int. J. Mech. Prod. Eng. 3(11), 98–101 (2015) 6. Merlin, J.T., Chitaranjan, P.: Design and analysis of pressure vessel with different end domes. Int. J. Sci. Eng. Technol. Res. 6(8), 1225–1233 (2017) 7. Pervan, N., Muminovic, A.J., Muminovic, A., Delic, M.: Development of parametric CAD model and structural analysis of the car jack. Adv. Sci. Technol. Res. J. 13(3), 24–30 (2019) 8. Pervan, N., Muminovic, A.J., Mesic, E., Hadziabdic, V., Delic, M.: Design and kinematic analysis of the car jack. TEM J. 9(3), 924–928 (2020) ˇ c, M., Meši´c, E., Pervan, N.: Analytical calculation and FEM analysis main 9. Deli´c, M., Coli´ girder double girder bridge crane. TEM J. 6, 48–52 (2017) 10. Mesic, E., Muminovic, A.J., Repcic, N.: Geometrical Modelling and Structural Analysis of the Sarafix Fixator Configurations. In: Annals of DAAAM for 2012 & Proceedings of the 23rd International DAAAM Symposium, pp. 69–74 (2012) 11. Meši´c, E., Avdi´c, V., Pervan, N., Repˇci´c, N.: Finite element analysis and experimental testing of stiffness of the Sarafix external fixator. Procedia Eng. 100, 1598–1607 (2015) 12. Meši´c, E., Avdi´c, V., Pervan, N.: Numerical and experimental stress analysis of an external fixation system. Folia Medica Facultatis Medicinae Universitatis Saraeviensis 50(1), 74–80 (2015) ˇ c, M., Meši´c, E.: Theoretical and experimental analysis of the main 13. Deli´c, M., Pervan, N., Coli´ girder double girder bridge cranes. Int. J. Adv. Appl. Sci. 6(4), 75–80 (2019) ˇ c, M., Avdi´c, V.: Stiffness analysis of the Sarafix external fixator 14. Pervan, N., Meši´c, E., Coli´ based on stainless steel and composite material. TEM J.ournal 4(4), 366–372 (2015)
Analytical Calculation and FEM Analysis of Single Girder Bridge Crane Made Out of Hot-Rolled Profiles Enis Muratovic(B) , Mirsad Colic, Adil Muminovic, and Isad Saric Department of Mechanical Design, Faculty of Mechanical Engineering, University of Sarajevo, Vilsonovo setaliste 9, 71000 Sarajevo, Bosnia and Herzegovina [email protected]
Abstract. With the development of science and rapid growth of engineering needs for suitable structural analysis softwares, FEM (Finite Element Method) analysis has become one of the main tools for design process. Combination of hardware and software resources gives complete geometric model of any assembly with accurate results for research field. At the same time, this approach enables effective realtime data manipulation that reduces design process time to minimum. Practical significance of this design system is reflected in more convenient, faster and safer task completion. Bridge cranes are one of the most widely used cranes for material transport in modern production and they represent complex systems, composed of many subsystems with different coupling characteristics. Empirical design is most often used for crane’s necessary structure calculations and other design parameters that have direct impact on production performance. Bridge girder, as a main component in special machinery equipment, requires accurate perfomance data results like bending stresses and deflections that meet the design requirements. The result of this research is analytical calculation of single girder bridge crane, with determined maximum bending stress and deflection on bridge girder. After calculation is performed, geometric 3D model of single girder bridge crane is created in CATIA (Computer Aided Three-dimensional Interactive Application) software. Geometric 3D model was than subjected to FEM analysis in same software, whereupon results comparison has been done. Keywords: Finite elemene method · Design · Bridge crane · Bending stress · Deflection
1 Introduction The bridge crane represents lifting equipment for material transport. They usually operate over the warehouses, workshops and material fields [1]. Currently, there are various uncertainties in the metal structure of bridge crane, such as size parameters, material properties, and external load [2, 3]. As a key part of bridge crane structure, the security of the main girder is a powerful guarantee for the reliable operation of the entire device [4]. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 54–61, 2021. https://doi.org/10.1007/978-3-030-75275-0_6
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Various types of cranes are used in industries with many being highly specialized. One of them is single girder bridge crane that is consistent of single bridge girder supported on two end trucks as shown on Fig. 1.
Fig. 1. Single girder bridge crane
The main goal of this research is to design the bridge crane superstructure and to calculate the critical bending stresses and deflection values with their location, caused due to movement of trolley hoist mechanism on main girder’s bottom flange [5]. Crane design parameters and hot-rolled profiles used for design process are shown in Table 1. Table 1. Single girder bridge crane design parameters and hot-rolled profiles used for design process Design parameter Maximum load capacity [kN] 20 Total bridge crane span [m]
8
Hot-rolled profile function Bridge girder
IPE 300
End truck
UPE 140
Diagonal brace (optional)
L80 × 80 × 6
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Diagonal brace requirement is optional, and it’s used for larger bridge girder spans. Since the span of considered girder is 8 m, diagonal braceis used for additional horizontal stiffness of crane’s superstructure, especially during the cycles of crane actuating and stopping.
2 Analytical Calculation When the bridge crane is working, wheels of the trolley will press on the bridge and generate a down-ward bend [6, 7]. It is required to calculate most severe operating conditions with full load, where maximum stress and maximum deflection occurred shouldn’t exceed the material yield strength and conform to requirements of static strength and static stiffness [8]. 2.1 Calculation of Maximum Load Capacity Design process starts with selection of bridge girder profile. Analytical calculation of maximum load capacity for considered IPE 300 profile is represented as simple static problem shown on Fig. 2, where bridge girder is represented as a beam [9].
Fig. 2. Analytical model for calculating maximum load capacity
Maximum bending stress is calculated via condition: Msmax ≤ σdoz Wy
(1)
whereas: Msmax – maximum bending moment, Wy – resistant moment of inertia of I profile (for y axis), σmax – maximum bending stress. Maximum load capacity is obtained form expression (1) and amounts 44,56 kN.Next step in calculation is considering lateral torsional buckling where stability condition is represented with (2). σmax ≤
σD σv = αp · χD · υ υ
(2)
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whereas: σmax – maximum bending stress, σD – permitted lateral torsion buckling stress, υ = 1, 5 – degree of safety, αp – coefficient of cross-sectional shapes, χD – nondimensional coefficient of lateral torsional buckling, σv – yield strength. Maximum capacity load, which doesn’t lead to torsional buckling, for bridge girder to operate with amounts 28 kN. 2.2 Stress Calculation Bridge girder is loaded with actuating and driven trolley wheels forces T1 and T2 . Analytical model for maximum bending stress calculation is shown on Fig. 3.
Fig. 3. Analytical model for calculating maximum stress moment
Maximum bending stress is located on section I of bridge girder. By setting static equation for location B we have: FA · L − R · 0, 5(L − e1 ) = 0
(3)
whereas: FA – reaction force on loacation A, L – total girder span, R – summary load of forces T1 and T2 , e1 – distance between actuating wheels and summary load location. Maximum bending moment is equal to: MImax =
R (L − e1 )2 . 4·L
(4)
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Mimum bending stress is equal to: σsI =
MImax ≤ σdoz Wy
(5)
whereas: σsI – bending stress on section I, MImax – maximum bending moment, Wy – resistant moment of inertia of I profile (for y axis), σdoz – marinal stress. σsI = 75, 13 MPa < 160 MPa
(6)
2.3 Deflection Calculation Bridge girder deflection is most influent factor for capacity. Location of maximum deflection is correspondent with maximum load location i.e. location of actuating trolley wheels. Deflection is calculated for two cases, first with trolley actuating wheels (Fig. 4) and second for trolley driven wheels. Therefore, two analytical models will be observed.
Fig. 4. Analytical model for displacement calculation
Girder deflection for actuating wheels load T1 is calculated with Eq. (7): a 2 b 2 l3 T1 1 1 · f1 = · · 3 E · Iy l l
(7)
whereas: T1 = 12603,89 N – force on actuating trolley wheels, L = 8 m – total girder span, a1 = x = 0, 5(l − e1 ) = 3,871 m, b = l − a1 = 4,129 m, E = 210 GPa– Young’s modulus for steel, Iy = 8356 cm4 – moment of inertia (y axis). Deflection for first considered case amounts f1 =7,6 mm, and using similar model for second case deflection of f2 =5,7 mm is obtained.
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According to the requirements of crane design combined with actual usage requirements for the stiffness of the crane bridge girder are as follows: f ≤
1 ·L 600
(8)
Total bridge girder deflection is sum of f1 and f2 : f = f1 + f2 ≤
1 ·L 600
(9)
Total deflection amounts 13,3 mm and satisfies the condition on right-hand side of (9).
3 The Formation of Geomatric Model and Fem Analysis In order to perform finite element method calculations, a geometric model of the crane superstructure was made in CATIA software system with the identical geometric specifications in accordance with research object. For such a model, several loads were applied to the locations of trolley hoist construction wheels for case of maximum bending stress on bridge girder [10–13]. Geometric models is shown on Fig. 5.
Fig. 5. Single girder bridge crane geometric model
The calculation capacity and calculation efficiency must be considered when setting mesh. The finer the elements meshed are, the more accordant FEM model is with the actual condition [14, 15]. To achieve better accuracy, uniform parabolic tetrahedron (TE10 finite element type)mesh was used with size of 20 mm and absolute sag of 40 mm. Information of structure computation is given in Table 2. Table 2. Structure computation Number of nodes
254481
Number of elements 125521 Number of D. O. F
763443
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Fig. 6. Maximum Von Mises stress
Fig. 7. Maximum deflection
Structural analysis results are shown in Figs. 6 and 7 where maximum bending stress and maximum deflection are shown. Comparative results for analytical calculation and FEM analysis are shown in Table 3. Table 3. Comparison of analytical results and FEM analysis Stress [MPa] Deflection [mm] Analytics
75,13
13,3
FEM analysis 78,62
12,9
Deviation
3,00%
4,65%
As expected, maximum bending stress is located under actuating trolley wheels, and maximum deflection is at the mid-span, as shown in Figs. 6 and 7.
4 Results and Discussion The maximum stress obtained from structural analysis is in contact area of trolley hoist mechanism actuating wheels and it amounts 78,62 MPa, which is 4,65% higher than the result obtained with analytics. The maximum deflection is in the mid-span of girder and it’s value is 12,9 mm that is 3% lower than calculated deflection. Considering expression (8), it is notable that maximum deflection values are very close to permissible value.
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This can lead to dangerous working regimes, especially for cases of impact workloads. In this case, during the design process, vertical trussneeds to be specified. That way, better stiffness in vertical direction will be accomplished, where bridge crane superstructure has enhanced security and reliability.
References 1. Qing, Y., Xu Dong, M.: The performance analysis of double beam bridge crane based on computer simulation. Key Eng. Mater. 584, 107–111 (2014) 2. Saric, I, Muminovic, A.J.: Product Development and Design. Faculty of Mechanical Engineering Sarajevo, Sarajevo (2018) 3. Meng, W., Yang, Z., Xi, X., Cai, J. Reliability analysis-based numerical calculation of metal structure of bridge crane. Math. Probl. Eng. 5 (2013) 4. Liu, N., Xiang, D., Mou, P., Ren, Y., Xie, N.: Fatigue research on welding joint of the main girder in bridge crane. AMR 711, 323–326 (2013) 5. Sakurikar, O.K., Kushare, D.V.: Review of overhead crane and analysis of components depending on span. Int. Res. J. Eng. Technol. (IRJET) 3(5), 1004–1008 (2016) 6. Yifei, T., Lijin, L., Guomin, S., Dongbo, L., Xiangdong, L.: Chamber deformation estimation of bridge crane and energy-consumption analysis. Proc. Instit. Mech. Eng. Part B: J. Eng. Manuf. 230(2), 313–318 (2016) 7. He, Y.B., Zhang, Y., Yang, B.K., Liu, S.W., Chen, D.F.: Finite element analysis in dynamic conditions of bridge crane beam. AMM 331, 70–73 (2013) 8. Shen, G.M., Li, D.B., Yang, Z., Li, X.D.: Research on arch curve of bridge crane girder based on hyperworks. AMR 320, 382–387 (2011) 9. Delic, M., Colic, M., Mesic, E., Pervan, N.: Analytical calculation and fem analysis main girder double girder bridge crane. TEM J. 6(1), 48–52 (2017) 10. Haniszewski, T.: Strength analysis of overead traveling Cranw with use of finite element method. Transp. Probl. 9(1), 19–26 (2014) 11. Saric, I., Muminovic, A., Delic, M., Muminovic, A.J.: Development of integrated intelligent CAD system for calculation. Des. Dev. Bridge Crane J. Appl. Sci. Eng. 23(2), 349–355 (2020) 12. Yifei, T., Wei, Y., Zhen, Y., Dongbo, L., Xiangdong, L.: research on multidisciplinary optimization design of bridge crane. Math. Probl. Eng. 10 (2013) 13. Nang, Z.Y.: Structural optimization research on girder of 200t bridge crane based on ANSYS. AMR 430–432, 1078–1711 (2012) 14. Sowa, L., Kwiaton, P.: Mathematical modeling of mechanical phenomena in the gantry crane beam. J. Appl. Math. Comput. Mech. 16(3), 97–104 (2017) 15. Muminovic, A., Saric, I., Mesic, E.: Computer-Aided Design (CAD), Faculty of Mechanical Engineering Sarajevo, Sarajevo (2012)
Size and Topology Optimization of Structures Ermin Husak(B) and Mehmed Mahmi´c Technical Faculty, University of Biha´c, Irfana Ljubijanki´ca bb., 77000 Biha´c, Bosnia and Herzegovina
Abstract. In the first part of this paper, the results of size optimization of truss are given. A minimum mass was required as an objective function. Four optimization methods were used in optimization: nonlinear programming, genetic algorithms, particle swarm optimization and ant colony optimization. The obtained results are presented in the corresponding table. The second part of the paper presents the results of topology optimization using ANSYS software. In this case, the minimum value of compliance of structure for different mass values is used as an objective function. Keywords: Optimization · Size · Topology · Truss · Structure
1 Introduction Structural optimization is a popular field of research, especially in the field of mechanical engineering, civil engineering, aeronautics, mining, nuclear engineering, as well as some other technical areas [1–3]. In the optimization of structures, the three most common types of optimization are: size optimization, shape optimization and topology optimization [4, 5].With the development of optimization methods, different optimization methods have been used to optimize structures. From the first paper, which is considered in this field “The limits of economy of material in frame-structures” by Antony Michell published in 1904, where the author used variational calculus for optimization, through gradient methods such as linear programming, nonlinear programming methods and to modern methods such as genetic algorithms, particle swarm optimization, ant colony optimization have been used in structure optimization [6–12]. The two main goals are set before all these methods and that is to get the global optimum and get the global optimum in the shortest possible time. This research has enabled the optimization of structures in recent years to be incorporated as a possible option in the design process of most well-known commercial software. As an example of research in this paper, the size optimization of truss with different methods of optimization and as well as the optimization in the commercial software ANSYS is given.
2 Size Optimization of Truss For the example of optimization and comparative analysis with discrete variables, the known example of size optimization of truss with ten bars is used [1], as shown in Fig. 1. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 62–67, 2021. https://doi.org/10.1007/978-3-030-75275-0_7
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In this example, it is necessary to minimize the weight of the truss with ten bars, cross sections need to be selected from a discrete set consisting of standard values. This set is made up of values (10.45, 11.61, 12.83, 13.74, 15.35, 16.9, 16.96, 18.58, 18.9, 19.93, 20.19, 21.8, 22.38, 22.9, 23.41, 24.77, 24.96, 25.03, 26.96, 27.22, 28.96, 29.61, 30.96, 32.06, 33.03, 37.03, 46.58, 51.41, 74.19, 87.09, 89.67, 91.61, 99.99, 103.22, 109.03, 121.29, 128.38, 141.93, 147.74, 170.96, 193.54, 216.12). Truss is consisted of ten aluminium bars (densityρ = 2768 kg/m3 , modulus of elasticity E = 69·103 MPa) and six nodes. Load is with two concentrated forces F = 450 kN. The dimensions of the truss are defined by the dimension L = 9,1 m. Optimization with discrete variables from a defined set, ie searching for the minimum mass of a truss, must be performed with the following constraints:the maximum stress of the bars must not exceed 172 MPa and the displacement in the nodes along the x and y coordinates must not exceed 5.08 cm.
Fig. 1. Aluminium truss
The objective function is defined in according to the Eq. (1): √ √ √ √ Min f (x) = ρ · L(x1 + x2 + x3 + x4 + x5 + x6 + 2x7 + 2x8 + 2x9 + 2x10 ) (1) In order to be able to set two constraint functions, it is first necessary to determine how the system will be analyzed. Since It is also a complex elastic system, only numerical methods are acceptable. The truss with 10 bars is analyzed by the finite element method according to the equation in the matlab programming language, which for each value of input variables gave the system response values, which in this case is the displacement of nodes and the stress [7, 13–15]. Size optimization of the truss, using discrete variables, was done by the methods: – – – –
nonlinear programming NP, genetic algorithm GA, particle swarm optimization PSO, ant colony optimization ACO.
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The results obtained after optimization with the four mentioned methods are given in Table 1. Table 1. Comparison of the results of optimization methods in discrete optimization of a truss with 10 bars
As can be seen in Table 1 the best value of the objective function i.e. the smallest truss mass was obtained by optimization by genetic algorithms 2557.16 kg. Then the next best method is particle swarm optimization where the truss mass was obtained 2617.56 kg. The next is nonlinear programming where a mass of 2638.24 kg was obtained, and the worst result was a mass of 2968.19 kg obtained by the ant colony optimization method.
3 Topology Optimization Structural topology optimization can be divided into optimization through discrete elements and optimization of continuous systems. In optimization over discrete elements, the solution area is represented by predetermined possible locations of the members of the discrete structure such as truss, frames and panels (Fig. 2).
Fig. 2. Discrete topology optimization of truss
In the continuous approach, the solution area is represented as a continuum of material/voids or very low density material. By varying the void/material distribution or the
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Fig. 3. Optimization of continuum systems
density of a material with an structure, it is possible to display different topologies at each location in the continuum of the structure which is shown in Fig. 3. In recent years, more and more commercial software provides the ability to optimize the topology of structures. As an example in this paper, topology optimization in ANSYS is presented. A two-dimensional sheetwhose boundary conditions and loads are the same as for the example shown in Fig. 1 was chosen as the area of the structure which is shown in Fig. 4. Type of objective function which ANSYS offers is compliance, while as a constraint mass is selected.
Fig. 4. Area of possible structure
Fig. 5. Optimal topology with 50% mass
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Fig. 6. Optimal topology with 40% mass
As can be seen from Figs. 5 and 6, by optimizing the topology with a continuous approach in ANSYS, the topology of the structure is obtained, which by its shape represents a truss. It is well known that truss is structures that have a high rigidity in relation to the mass of the system, unlike beams. For the purpose of research, we set different mass constraints for the same value of the objective function. The optimization results for the 50% and 40% mass constraints are shown in Figs. 5 and 6.
4 Conclusion Structure optimization has become one of the important stages in product design. Longterm research in the field of optimization methods as well as types of optimization has enabled the implementation of structure optimization in many commercial software packages so that today many CAD systems have the ability to optimize the topology. The three basic criteria in choosing an optimization method or algorithm are robustness, effectiveness, and exactness. For this purpose, the results of size optimization of truss are given where it is seen that the best optimal value is obtained by genetic algorithm. As an example of the use of commercial software in structure optimization, topology optimization in ANSYS simulation software is given.
References 1. 2. 3. 4.
Arora, J.: Introduction to Optimal Design. McGraw-Hill Book Company, New York (1989) Cox, H.: The Design of Structures of Least Weight. Pergamon Press, Oxford (1965) Kirsch, U.: Structural Optimization—Fundamentals and Applications. Springer, Berlin (1993) Husak, E., Karabegovi´c, I., Isi´c, S.: Mogu´ci tipovi optimizacije elastiˇcnih sistema. In: Proceedings: New Technologies, NT 2016, Mostar, pp. 135–140 (2016) 5. Husak, E., Isi´c, S.: Optimization as One of the Basic Supports of Industry 4.0, Chapter in Handbook of Research on Integrating Industry 4.0 in Business and Manufacturing, IGI Global, pp. 192–212 (2020)
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6. Colorni, A., Dorigo, M., Maniezzo, V.: Distributed optimization by ant colonies. In: Procesdings of ECAL91-European conference on artificial life, pp. 134–142. Elseiver publishing, Paris, France (1991) 7. Luh, G.C., Yi Lin, C.: Optimal design of truss-structures using particle swarm optimization. Comput. Struct. 89(23–24), 2221–2232 (2011) 8. Kaveh, A., Hassani, B., Shojaee, S., Tavakkoli, S.M.: Structural topology optimization using ant colony methodology. Eng. Struct. 30, 2559–2565 (2008) 9. Husak, E., Karabegovi´c, I., Isi´cSafet, Karabegovi´c, E.: Application of new optimization methods in structural design. In: Proceedings: 2nd International Scientific Conference on Engineering MAT 2012, Antalya, Turkey, pp. 140–143 (2012) 10. Husak, E., Karabegovi´c, I., Isi´c, S.: Uporedna analiza gradijentnih i heuristiˇckih metoda kod optimizacije konzole. In: Proceedings: New Technologies, NT 2015, Mostar, pp. 193–200 (2015) 11. Husak, E., Karabegovi´c, E., Brezoˇcnik, M.: Korištenje heuristiˇckih metoda u optimizaciji elastiˇcnih struktura. In: Proceedings: New Technologies, NT 2015, Mostar, pp. 186–192 (2015) 12. Jovanovi´c, M., Husak, E.: Optimization Based on Simulation of Ants Colony, New Technologies, Development and Applications II. Lecture Notes in Networks and Systems, vol. 76, pp. 96–10, Springer, 2020 (2019) 13. Rajeev, S., Krishnamoorthy, C.S.: Discrete optimization of structures using genetic algorithms. J. Struct. Eng. 118(5), 1233–50 (1992) 14. Isi´c, S.: Non-gradient optimization method for minimum mass truss design. In: 5th International scientific Conference RIM 2005, Biha´c, pp. 343–348 (2005) 15. Isi´c, S.: Combinatorial approch to descrete minimum mass design. In: 2nd International Scientific Conference RIM 1999, Biha´c, pp. 89–96 (1999)
Analysis of Impact of Possibilities of Modern Computers on Applicability of Combinatorial Optimization Safet Isi´c(B) , Munib Obradovi´c, and Semir Mehremi´c Mechanical Faculty, University “Džemal Bijedi´c” in Mostar, 88000 Mostar, Bosnia and Herzegovina [email protected]
Abstract. Combinatorial optimization is the simplest method of optimizing problems with discrete values of design variables. Because of large number of possible combinations and time-consuming optimization process, this method is not popular and significantly used. This paper presents an analysis of the impact of the rapid increase in the speed of modern computers on the possibilities of applying combinatorial optimization. The analysis was performed on the problem of mass minimization of plane truss with discrete values of rod cross section. Up to 1010 possible combinations have been tested on processors of different speeds. Keywords: Combinatorial optimization · Combination number · CPU frequency · Process acceleration
1 Introduction Optimum design of construction under some specified constraints is almost required. In many practical problems, for construction dimensions standard discrete values should be determined. Combinatorial optimization is the simplest method of optimizing problems with discrete values of design variables. This method always finds the global extreme of the objective function, unlike classical methods based on gradient calculation or modern heuristic methods. A large number of combinations of discrete variable value distributions for problems with large number of design variables leads to a time-consuming solution process [5], so this method has not been used significantly. Some enhancements are made by combination decreasing and process acceleration. Number of combinations to be tested are reduced by introducing additional constraints regarding member groups, i.e. setting which members are defined by same design variable [1, 5]. Change between design in two successive combination has been used to accelerate optimization process significantly [8]. These results show that improvements are possible, and that processor speed is limiting factor. Results are given for one processor speed only. We are faced by rapid increasing computer performances. Because of that and relative simplicity of the method and a concept, reanalysis of possibilities of combinatorial optimization could be reasonable. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 68–73, 2021. https://doi.org/10.1007/978-3-030-75275-0_8
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This paper presents an analysis of the impact of the rapid increase in the speed of modern computers on the possibilities of applying combinatorial optimization. The analysis was performed on the problem of mass minimization of plane truss with discrete values of rod cross section. Up to 1010 possible combinations have been tested on processors of different speeds. It is analyzed dependency of CPU speed characteristics, CPU Mark and duration of optimization for given combination number. From this dependency could be extrapolated future improvement of method applicability in future time.
2 Problem Formulation 2.1 Problem of Discrete Optimization Problem to be solved in discrete minimum mass design of structure, consisted of M members for which is available set of N discrete sizes {y} = {y1 , y2 ,…, yN }, is the following: Minf ({x}) = {d}T · {x} g({x}) ≤ 0
(1)
h({x}) = 0 where are: – {x} = {x}(i) = {x 1 (i) x 2 (i) … x M (i) }T vector of design variables. – {d} = {d 1 d 2 … d M }T is vector of given characteristics of structural members, such that {d}T ·{x} represents mass of the structure, – i denotes ith combination of arrangement of discrete sizes {y}, and T means transpose, – g({x}) – is vector of inequality constraints to be satisfied, and – h({x}) – is vector of equality constraints. In case of minimum mass design of elastic structure, analysis is performed by finite elements method and members are almost finite elements. Inequality constraints could be concerned to displacement, stress, buckling force and eigen frequencies. Equality constraints are not often included in optimization problems of minimum mass structure design. Optimization process and implementation is presented by simplified computer block chart (Fig. 1a). Generation of combination (distribution of given discrete values) are presented in Fig. 2b. It could be determined that total combination number is K = MN
(2)
For relatively small problem of ten members and ten available discrete values, we have 1010 different combination to be checked. One second of one combination analysis leads to hundredths year optimization process. Optimization improvement is possible by reduction of combination by setting members of same discrete values. In [5] in 1999, by this combination reduction 710 problem was solved. Exploiting the fact that combination almost differ in one value, fast reanalysis is introduced in and 1010 problem is solved in 10.94 h [8].
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Fig. 1. Common block diagram of combinatorial optimization and combination generation.
2.2 Test Problem Test ten bar truss is shown in Fig. 2a. This truss is often used to testing and comparison of optimization methods. The truss is subjected to displacement constraint equal to 5.08 [cm] imposed on all nodes and stress constraints equal to 17.243 [kN/cm2 ] imposed on all bars. The set of available discrete sections contains ten following sizes of area (in cm2 ): {y} = {232.2, 174.2, 122.6, 77.4, 45.2, 25.8, 12.9, 6.4, 3.2, 0.6}. Optimum design giving minimum mass is {x} = {0.6, 45.2, 0.6, 25.8, 12.9, 77.4, 77.4, 25.8, 45.2}.
Fig. 2. Test problem- ten bar truss subjected to stress and displacement constraints.
Speed of optimization process is tested increasing available discrete values from 1 to 10. Speed of optimization process for different number of combinations is tested on CPU of characteristics given in Table 1 [9]. For testing purpose, the following are analyzed: – Average CPU time per combination for different total combination number and different processors, – Dependency of average CPU time on processor performances. Testings are performed only for faster method of combinatorial optimization, i.e. method based on fast reanalysis.
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Table 1. CPU characteristics of used computers. No.
CPU
CPU clock
CPU mark
Integer/Floating point math [MOps/Sec]
1
Pentium III
1.9 GHz
0 , dPnom = 0 or decreases < 0 . but remains constant dPdnom λ dλ Condition (1) can be fulfilled by using a variable gear ratio transmission mechanism in the load capacity limiter. The gear ratio must increase when the limiter moving parts’ motion after the start of its operation. To implement a variable gear ratio, a roller mechanism is proposed (the rollers are arranged in the form of diamond-shaped sets) (Fig. 1).
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Fig. 1. Design diagram of the load capacity limiter with a roller transfer mechanism (the rollers are arranged in the diamond-shaped sets form)
The load capacity limiter is installed on the stand 1, while the transfer mechanism is installed between the movable base 2 under load and the fixed plate 3. The transfer mechanism is made in the form of several sets of rollers, each set consisting of four rollers 4 and 5. On the right and left, the rollers 4 are preloaded through the prisms 6 by pre-compressed springs 7. The spring 7 force is selected so that at the nominal force of the load limiter, the rollers are compressed between the base 2 and the plate 3 and no relative movement takes place. The rightmost spring contacts the screw stop 8, screwed into the transmission mechanism housing 9. With the auxiliary of stop element 8, the springs 7 are pre-compressed. The leftmost spring contacts through the heel 10 with the transmission mechanism housing 9. The heel 10 bears a central hole through which the prism 6 actuates by means of the rod 11 the microswitch 12 installed in the housing 9. When the crane is overloaded, the base 2 is lowered due to that the rollers 4 and 5 diverge, and the rollers 4 move towards the prisms 6, overcoming the resistance of the precompressed springs 7. The springs 7 are additionally compressed therefore there occurs the possibility to move rollers 4 horizontally. Moving, the prism 6 transfers the action to microswitch 12, which disables the drive of the lifting mechanism when overloaded. Overload eliminated, in such a way, the rollers return to their initial position under the action of the spring 7. 2.3 Results According to the calculation scheme (Fig. 2), drawing up the equilibrium equation for each roller, we determine the relationship between the nominal load limiter actuation forcen Pnom and the required pre-compression force Ppr of the springs. Ppr =
Pnom (sinα − f · cosα) · , n (cosα + f · sinα)
(2)
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where n – is the number of rollers supporting the base 2, f – is the coefficient of sliding friction between the rollers.
Fig. 2. Calculation scheme of the roller transfer mechanism to determine the relationship between the forces Pnom and Ppr
We determine the transfer mechanism springs stiffness index at which the greatest transmitted force of the load capacity limiter will correspond to the beginning of the roller movement when triggered. Here, condition (1) must be met. We represent the dependence (2) in the form n Ppr + c · λ (3) Pnom = (sinα−f ·cosα) , (cosα+f ·sinα)
where Ppr – the spring pre-compression, c – spring stiffness. Having differentiated (3), taking into account that d λ = (r1 + r2 )cosα · d α, we get G · D · n · c − n Ppr + ·λ f 2 + 1 (r1 +r12 )cosα dPnom = , (4) dλ D2 where D = sinα − f · cosα, G = cosα + f · sinα.
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Since, D2 = 0, when λ = 0, in other words, when the transmission mechanism is triggered at the very beginning of the roller displacement, the spring stiffness will be Ppr f 2 + 1 , (5) c≤ G · D · (r1 + r2 )cosα Assuming f = 0 and considering that sinα·cosα 2 ≤ 0, 39, we get the spring stiffness value that guarantees the transmission mechanism maximum actuation force as early as in the beginning of the roller displacement,
c≤
Ppr 0, 39(r1 + r2 )
.
(6)
Thus, when the load limiter’s measuring springs stiffness defined by expression (6), the condition (1), and the parts’ moving masses rundown energy is absorbed after disabling the crane lifting mechanism motor. A roller mechanism with a staggered rollers arrangement can be used as a transfer mechanism with a variable gear ratio [9]. Compared to the mechanism in Fig. 1, it has some disadvantages, namely the presence of rolling friction between the rollers and the support planes that leads to an uneven load distribution between the rollers, and possible fluctuations in these friction forces do reduce the accuracy of load limiter triggering.
3 Conclusion 1. The most commonly used method of bridge cranes overload protection by disconnecting the lifting mechanism drive electric motor does not provide the necessary accuracy of overload protection for the crane. 2. To improve the accuracy of bridge cranes overload protection, it is proposed to use a method for disconnecting translationally moving parts of the lifting mechanism with simultaneous disconnection of this mechanism drive electric motor. 3. Suggested is a condition under which the absorption of load capacity limiter parts’ moving masses run-out energy is provided. This condition provides that when the crane overloaded the load-carrying capacity limiter, will act on the protected object in such a way that the load growth rate in the lifting mechanism drive power circuit after the limiter operation started becomes equal to zero or less than zero. 4. Developed is the design scheme of the load-carrying capacity limiter with a roller transfer mechanism (rollers are arranged in the form of diamond-shaped sets). 5. It is established that in order to absorb the moving parts running out energy the transmission mechanism must have a gear ratio that increases as the moving parts move, with the measuring body spring constant stiffness. 6. The dependence for determining the stiffness of load limiter’s measuring body spring which provides the parts moving mass run-out energy absorption after disconnecting the crane lifting mechanism electric motor is found.
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References 1. Mudrov, A.: Decreasing the peak loads at launching the cranes load lifting mechanism, technology and organization of construction. News Kazan State Univ. Arch. Civil Eng. 2(44), 239–245 (2018) 2. Zavialov, V.M., Gusev, A.V.: Automatic limitation of dynamic loads at the bridge crane lifting mechanism electric drive. News Tomsk Polytech. Univ. 318(4), 151–154 (2011) 3. Menzel, U.: Krane – Einsatzererfahrungen und Entwicklungstendenzen. Kranfachtagung 14, 77–86 (2006) 4. Vöthi, S.: Hubwerke mit Sicherheitsbremsen, Teil 1: Belastungen dev Komponenten, p. 3. Hebezeuge und Fördermittel, Heft (2015) 5. Schmeink, D.: Dynamische Beanspruchung von Hubwerksgetrieben. Tagungsband 22. Internationale Kranfachtagung, Magdeburg (2014) 6. Orlov, D.Y.: Improving the safety of bridge-type cranes operation based on a load capacity limiter with advanced functionality: Abstract of the dissertation thesis ... candidate of technical sciences, Tomsk, Russia (2004) 7. Stolyarov, D.P.: Improvement of the protection and technical condition control system for the bridge type crane: Abstract of the dissertation thesis ... candidate of technical sciences, Tomsk, Russia (2010) 8. Semenyuk, V., Lingur, V.: Feasibility study of the bridge type load-lifting cranes protection against systematic overloading. In: Proceedings of the Tavrian National University named ater V. I. Vernadsky. Series: Engineering science. – 2018, vol. 29, no. 68, no. 4, pp. 19–24 (2018) 9. Semenyuk, V., Lingur, V., Punchenko, N., Falat, P.: Roller function-generating mechanism preventing the crank-drive machines’ overloads. In: Mechanisms and Machine Science, vol. 70 (Springer. Engineer of the XXI Century), pp. 29–38 (2020)
Reverse Engineering in the Remanufacturing: Metrology, Project Management, Redesign Viktor Ivanov1(B) , Lubomir Dimitrov2 , Svitlana Ivanova3 , and Mariia Volkova3 1 Odessa National Polytechnic University, Odesa, Ukraine
[email protected] 2 Technical University of Sofia, Sofia, Bulgaria 3 South Ukrainian National Pedagogical University named after K.D. Ushynsky,
Odesa, Ukraine
Abstract. The analysis of the concepts used for engineering analysis of existing product samples is given: Remanufacturing, Repair, Reverse engineering, Redesign, Repurposing. In all cases, there is a decryption phase consisting analysis of technical state and identification. The identification involves the analysis of a design, the identification of units that make it up, the definition of technical specifications and the complete reproduction a technical documentation of existing product. The analysis of the technical condition and identification are presented using the approaches of the pattern recognition process. The problem of further use of the product after identifying the causes of destruction and studying the design and functionality is presented as the process of recognizing the project type: Repair, Redesign, Repurposing, etc. The developed approach was used to analyze the technical state and identification the transmission parameters. The design structure matrix and the morphological map of damage were used to determine the root causes of the transmission failure and the damage scenario. Keywords: Decision rule · Transmission design · Project types
1 Introduction The terms remanufacturing, repair, reverse engineering, redesign, upgrade, repurposing are used to denote a set of measures, when the damaged product, can again be used in any manner. The initial stage of the faulty equipment study is the decryption phase, which consists of subphases: the analysis of the technical state and the identification of its units and machine elements [1]. Along with metrology research, the identification of equipment parameters is based on the software systems CAD/CAM/CAE, which contain libraries of unified units, standard machine elements and standard parts of elements. After the identification phase, it is necessary to make a decision about the possibility of using this equipment as a whole or its individual units and elements. And also, to determine: it must be a repair, which requires the manufacture of machine elements are copies of damaged or repair and upgrading of equipment, or in the case when damage and wear are significant, you need to look for alternative equipment use. The manufacture of © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 169–176, 2021. https://doi.org/10.1007/978-3-030-75275-0_20
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machine elements, which are copies of damaged ones, is the task of reverse engineering [2]. Equipment can be disposed of, but the information obtained will provide the basis for the development of new designs - redesign, and this is also reverse engineering task. Therefore, we believe that the concepts of repair, upgrade, redesign and alternative use, it is advisable to consider as separate parts of a broader concept, which we call reverse engineering. A methodology has been developed in which the object is considered as a black box at the first stage [3]. Three variants of upgrade are possible: the product parameters change, the product design also changing, the information obtained is used to develop a fundamentally new product design [3]. A heuristic method is proposed for identifying the units that compose the product. The product architecture is then searched to determine the power flows required to implement product functionality [4]. Based on the modular structure of the product, an analysis is made of the effect of changing the output parameters of the product on its design [5]. In contrast to the above methodology, it is not a design change that is investigated, but small changes in the geometric dimensions of the parts. A DSM (design structure matrix) matrix is compiled in order to integrally assess the allowable changes [6]. An analysis of the changes, which are made in product design for the purpose of redesign, is carried out using a graph of weight coefficients [7]. The heuristic methods described above: the DSM matrix and the graph with weights coefficients are combined into one method to evaluating the functional interrelation of the changes that introduced into the design [8]. This approach has much in common with the heuristic method in evaluating power flows [4]. The search for the possible use of known transmissions in the form to the nodes of a CVT was performed using a morphological map [9]. To search for a new design, an interrelation graph was used. The final version of the design was obtained taking into account the analysis of power flows, and the evaluation of design options was performed using a matrix diagram [9]. As you can see, different authors use the same set of heuristic methods to solve problems in various fields of machinery [10]. In some publications, the object was considered as a black box. The identification stage is in almost all studies. So, de facto, researchers consider reverse engineering as a whole or its separate phases using the pattern recognition theory approach.
2 Research Methodology The transmission consists of a large number of unified units, standard machine elements and standard parts of machine elements. The parameters of the some nodes are known, due to their unification, and the dimensions of standard machine elements are known too. The presence of standard discrete variables such as: modules, bearing diameters, center distances, etc., provide additional possibilities for decoding the parameters. This makes it possible not to measure all geometrical dimensions, but to determine only the key ones, on the basis of which can be determine other dimensions that associated with them. Standard dimensions are measured in the first place. These are the connecting dimensions, center distances, threaded connections dimensions, bearing diameters and so forth. The dimensions matrix is making up, which characterizes the product. The dimensions are compared with arrays of data dimensions in standards. After the coincidence of several dimensions, primarily center distances and connecting diameters, the
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model of the unit based on the assumption that they are designed on the framework of a certain standard is developing. The decision rule for recognizing the gearbox image is that all the center distances and the connecting dimensions should belong to the same standard. Then a hypothesis is built about other dimensions of the device in accordance with the selected standard. On the basis approximate dimensions, the exact values of the center distances, the bearings’ diameters and the parameters of the threaded joints are established. It is not the nominal geometrical dimensions that are measured, but the actual geometrical dimensions are due to the errors of manufacture, installation, and the errors of the measurement process and measuring instruments. That is, in the measurement process, instead of the existing physical prototype, we get an experimental model [11]. On the basis of the experimental model, a conceptual model is obtaining. This model contains information about the main geometric and strength characteristics. To form an ideal model, at the information contained in the conceptual model adds the designated steel grade, the assigned tolerances and fits, the technical requirements and the like. There is no need to achieve the complete identity of the ideal model and the original prototype, because the product is manufactured taking into account the available technological capabilities. A realistic model (GPS) reflects the parameters that can be obtained taking into account the features of the measurement method and the used metrological equipment. Thus reverse engineering can be represented as a chain: physical prototype, experimental model, conceptual model, ideal model, realistic model, new physical prototype. In case of equipment breakdown, it is necessary to resolve the issue of the objects to be reproduced. This is equipment as a whole, its units or individual elements. The choice between repair, upgrade or purchase of new equipment should be presented as a task for recognition of project parameters, which corresponds to repair, upgrade, etc. It is necessary to analyze the actual condition of the equipment, which involves the search for damage and determining the causes of equipment failure. The map is formed, in which the damaged parts and the degree of their damage are indicated. The decision rule for determining the causes of a failure is the coincidence of a map of damage with a morphological map built on the basis of a hypothesis about the causes of the failure. After establishing the causes of equipment failure and studying its design and functionality, the question of further use of the product arises. New equipment must be purchased from the manufacturer of that equipment (this type of project let’s call - original) or from another manufacturer (copy). And perhaps it is necessary to limit only to the replacement of a unit or unites that are purchased from the manufacturer of this equipment (this type of project let’s call - original assemble) or from another supplier (copy assemble). Perhaps the best option is to upgrade the equipment (this type of project let’s call - upgrade). If not all the equipment functions are used, then not all units should be repaired, some of them will not be required later (simplified). If for financial or organizational reasons the restoration of the equipment does not make sense, this equipment can be used with other functions (alternative use) or utilized (utilization). The projects parameters are: cost, duration, functionality, risk [12]. These parameters can be used as signs of a project type (Table 1). The decision rule for choosing a project
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type is the compliance of the project’s characteristic features with the established pattern of the project. Table 1. Assessment of signs of recognition projects Project types
Signs of recognition Costestimate
Duration
Functionality
Risk
Cost structure
Original
large
middle
large
small
QN + U + T
Copy
large
middle
middle
middle
QN + U + Z 1 + T
Original assemble
middle
small
large
small
AN + T
Copy assemble
middle
small
large
small
Z 1 + Z 3 or AN + Z 1 + T
Upgrade
large
large
large
large
Z 1+ Z 2+ Z 3
Simplified
middle
large
middle
large
Z 1+ Z 2+ Z 3
Alternative use
small
middle
other
middle
Z 1+ Z 2+ Z 3
Utilization
small
small
haven’t
small
U
Table 1 adopted the following designation of component costs: QN - new equipment, AN - new unites, T - transporting, U- utilization, Z 1 - identification phase, Z 2 - redesign, Z 3 - design and manufacturing. Analysis of the feasibility of projects: “Upgrade”, “Simplified”, “Alternative use” can be carried out using the following formula D−W = QR −(Z1 + Z2 + Z3 )−S0 , where QR - cost of the product after the upgrade; D - profit; W - risk; S 0 - residual value. It should be noted that for reverse engineering projects, the following conditions must be met. The total cost of works from all three phases should be less than the residual value and the cost of the possible replacement of unites - AN + T.
3 The Case of the Research Methodology Application An accident occurred in the port of Yuzhny at the TIS Mineral Fertilizers terminal on the granulator of ammonium sulfate. It is stopped due to the gearbox damage: pitting the surface of the teeth and unacceptable deformation of the gear rim. After strengthening the welded seams on the rim, the granulator was launched into operation, as its downtime leads to huge losses. Identification of the gearbox parameters and failed analysis are carried out. The gearbox contains a high-speed gear train whose gear wheel has teeth “A” cut into a ring “D”, as shown in Fig. 1. The hub “C” and the toothed ring are connected by flanges “B”. To increase the rigidity of the design, the flanges are connected by pipes “E”. The gear wheel is disposed on the shaft “G” located in the bearings “F”. The teeth of the gear wheel are engaged with the teeth of pinion “I”. The pinion toothed ring is made integral with the shaft “H”, located in the bearings “J”.
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Damage has the teeth of the pinion and gear wheels. The pitting of the pinion teeth «I» has signs of a progressive, but the pitting of the gear wheel teeth “A”, still allows it to be operated. The gear wheel has a welded designed. Flanges “B” are deformed; the pipes “E” are displaced in the axial direction and are in contact with one of the flanges on a small surface area. Damages also has rolling elements of the bearings “E” and “J”, and to a greater extent of the bearing “J”. Bearings can still be operation. Firth different scenarios of destruction are considered for determining the source of damages of gearbox machine elements: damage gearbox lubrication system; insufficient strength of the pinion teeth; insufficient strength of the welded gear wheel design; unacceptable wheel’s bearings deformation; unacceptable pinion’s bearings deformation.
Fig. 1. Gearbox design
A DSM matrix was constructed to analyze the interrelations between the elements of the gearbox (Table 2). A morphological map of damages was constructed to find the cause of damage to the gearbox (Table 3). The root cause of damage may be insufficient strength of the welded gear wheel design. The morphological map developed for such a case includes the elements “B” and “F” associated with them are the elements that must be damaged first of all: the toothed ring “D” and the hub “C”, as well as the teeth “A”. The root cause of damage may also be the insufficient strength of the pinion teeth, which is much less than the strength of the gear wheel teeth. In this case, due to their damage, the dynamic forces in the engagement increase, in addition, the uneven distribution of the load in the engagement increases. Increased forces in the engagement lead to an additional load of other elements. The toothed ring of the pinion is made integral with the shaft, its strength is sufficient. The welded gear wheel design is less durable more and the least rigid elements - flange and pipe are destroyed first. Morphological map prepared according to this scenario, completely coincides with the morphological map of damages. Thus, we conclude that the root cause of the destruction is the insufficient strength of the pinion teeth.
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A A B C D E F G H I J
x x x x x
B x
C x x
D x x
E x x
F x
G
H
I x
J
x
x x
x
x x x
x x
x
x x x
x
Table 3. Morphological map of damages
Elements Damage condition Damage haven’t Damage allow to extend the operation Damage which led to an accident
A B C D E F G H I
J
The gearbox functionality must be fully preserved. That is, we choose from three variants of the project: “Original”, “Original assemble”, “Copy assemble”. The first option is not suitable because of the high cost. The original assemble project is not suitable due to time constraints. The manufacturer is in the USA, the delivery time is significant.. Thus the project “Copy assemble” is selected. It is established - the gear train is designed in accordance with the ANSI standard. The standard diametric Pitch, P = 5 in. has been found. Geometric and strength calculations are made using the MechSoft software package. It was decided to increase pinion diameter and wheel rigidity due increase the pipes diameter. For preserve the former functionality it is necessary to: same center distance for use same housing; transmission ratio can be changed by less than 10% due to the requirements of the technological process; requirements of the teeth strength must be satisfied. Figure 2 shows a physical prototype - a helical gear pinion. The number of teeth increased: z1 = 23; z2 = 110, center distance aw = 14 in. is designed. Steel grade A322– 4340 with surface hardening is appointed. Total number of teeth in new and old gear trains are the same zΣ = 133. Center distance and the total value of the coefficient of correction x Σ = 1,219 is same too. The calculation of the contact strength showed that the existing gear trains had insufficient strength - the safety factor was S H = 0.88. The projected gear has a safety factor S H = 1.07. The ideal pinion model is created in the form of 3D solid model. The ten grade of accuracy of the toothed ring is assigned. To
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create a realistic model, boundaries have been found in which the geometric parameters must be measured. These boundaries are set on the basis of tolerances that correspond to tenth grade of accuracy, features of the measuring method and the metrological devices that used. A new helical gear shaft (physical prototype) has been manufactured, as shown in Fig. 3. It was tested in accordance with the tolerances established in the realistic model for the parameters: radial runout of the ring gear, deviation of the base tangent length, deviation of the helix angle. It is established that the manufactured pinion corresponds to a realistic model. Transmission tests under load and its further operation showed its sufficient strength.
Fig. 2. Initial physical prototype
Fig. 3. New physical prototype
4 Conclusion Terminology and approaches used by various researchers - Repair, Reverse engineering, Redesign, Repurposing, can be integrated in the concept of reverse engineering. In this case, reverse engineering is understood as a three-phase project. The first phase is the decryption that included two subphases: identification and technical state analysis of the existing product. The second phase is the choice of the project type. The third phase is the design and manufacture of a new product. This product is not necessarily a copy of the existing one and may have a different design and functionality. Identification is presented as a pattern recognition problem. Based on the analysis of the design and a small number of measurements, it is hypothesized that the product is made on the basis of a specific standard or standards. The decision rule, in this case, is the correspondence of the dimensions obtained after additional measurements to the assumed standard. For transmissions, it is advisable to put forward a hypothesis based on measurements of the center distance and the diameters of the input and output shafts. A technical state analysis is also presented as a pattern recognition problem. It is necessary to make a morphological map of damage elements. Hypotheses about various scenarios of product failure are put forward. For each of the scenarios, a morphological damage map is made. It was established that the decision rule for the analysis of the technical state is the coincidence of the morphological map in accordance with the hypothesis put forward and the morphological map of actual damage.
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The problem of further use of the product after identifying and analyze technical state the causes of destruction and studying the design and functionality are presented as the process of recognizing the project type. The features of the recognition project types were determined as follows: cost estimate, duration, functionality, risk. The decision rule for choosing a project type is the accordance of the project’s characteristic features with the established pattern of the project. Acknowledgments. This work has been accomplished with financial support by the Grant No BG05M2OP001-1.002-0011 “MIRACle (Mechatronics, Innovation, Robotics, Automation, Clean technologies)”, financed by the Science and Education for Smart Growth Operational Program (2014–2020) and co-financed by the European Union through the European structural and Investment funds.
References 1. Golovan, A., et al.: Improving the process of vehicle units diagnosis by applying harmonic analysis to the processing of discrete signals. SAE Technical Paper, No. 2018-01-1774(2018) 2. Buonamici, F., et al.: Reverse engineering modeling methods and tools: a survey. Comput.Aided Des. Appl. 15(3), 443–464 (2018) 3. Otto, K.N., Wood, K.L.: Product evolution: a reverse engineering and redesign methodology. Res. Eng. Des. 10(4), 226–243 (1998) 4. Stone, R.B., Wood, K.L., Crawford, R.H.: A heuristic method for identifying modules for product architectures. Des. Stud. 21(1), 5–31 (2000) 5. Masmoudi, M., Leclaire, P., Zolghadri, M., Haddar, M.: Dependency identification for engineering change management (ECM): an example of computer-aided design (CAD) - based approach. In: Proceedings of 20th International Conference on Engineering Design (ICED 15), vol. 3, pp. 199–208 (2015) 6. Clarkson, P., Simon, C., Eckert, C.: Predicting change propagation in complex design. J. Mech. Des. 126(5), 788–797 (2004) 7. Cheng, H., Chu, X.: A network-based assessment approach for change impacts on complex product. J. Intell. Manuf. 23(4), 1419–1431 (2012) 8. Masmoudi, M., Leclaire, P., Zolghadri, M., Haddar, M.: Engineering change management: a novel approach for dependency identification and change propagation for product redesign. IFAC PapersOnLine 50(1), 12410–12415 (2017) 9. Ivanov, V., Urum, G., Ivanova, S., Volkova, M.: Development of the positive engagement continuously variable transmission design with the application of graph theory. East.-Eur. J. Enterp. Technol. 1(3), 43–50 (2018) 10. Ivanov, V., Urum, G., Ivanova, S., Naleva, G.: Analysis of matrix and graph models of transmissions for optimization their design. East. Eur. J. Enterpr. Technol. 4(1(88)), 11–17 (2017) 11. Buonamici, F., et al.: Reverse engineering of mechanical parts: a template-based approach. J. Comput. Des. Eng. 5(2), 145–159 (2018) 12. Kolesnikov, O., et al.: Development of the model of interaction among the project, team of project and project environment in project system. East.-Eur. J. Enterp. Technol. 5(9), 20–26 (2016)
Investigation of the Influence of Tapered Thread Profile Accuracy on the Mechanical Stress, Fatigue Safety Factor and Contact Pressure Volodymyr Kopei1 , Oleh Onysko1(B) , Zinivii Odosii1 , Lolita Pituley1 , and Andrii Goroshko2 1 Ivano-Frankivsk National Technical University of Oil and Gas, Ivano-Frankivsk, Ukraine
[email protected] 2 Khmelnytskyi National University, Khmelnytskyi, Ukraine
Abstract. Generally the oil and gas drill-strings have a big number of threaded connectors between drill pipes. These ones named tool-joints influence the all drill-string operation characteristics, because they have to provide their reliability during the process of make-up, pumping and drilling. The most important parts of the connectors are pin and box tapered thread. The effect of deviations of the flank angle of the pin thread on equivalent stresses, fatigue safety factor and contact pressures in the drilling tool-joints is studded. Axisymmetric finite-element models of drill-string tool joints with threads 2 3/8 REG and 6 5/8 REG API-sizes has been developed for this. In order to reduce contact pressures on thread flanks, negative deviations of the loaded flank angle of the pin thread should be avoided and positive should be preferred (on the condition that fatigue strength is ensured). In this regard, it is recommended to change the tolerance limits of this flank angle from (29.5°, 30.5°) to (30°, 30.5°) for the pin thread, and do not change the tolerance limits for the box thread. Keywords: Tolerance limit · Tool-joint · Flank angle deviation · Fatigue · Contact pressure · Finite-element analysis
1 Introduction Drilling of the oil and gas wells is a process whose productivity largely depends on the quality and reliability of threaded connections between drill-string pipes. These connections are called as tool-joint and consist of a pin and a box. The tapered thread is their most important surface made by lathe. Therefore, the reliability and performance of the drilling depend on the accuracy of the turning process of the thread of the pin and the box and the strength of their material. Modern drilling methods require the use of steels with a tensile strength of up to 1200 MPa. The machining of threads on such hard-to machine steels can be effectively carried out by cutters with certain geometrical parameters. The most important of them is the rake angle and its value in the range from −10° up to +10° allows making a thread in such conditions. These negative and positive values obviously cause deviations from the thread profile. Therefore, it is important to © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 177–185, 2021. https://doi.org/10.1007/978-3-030-75275-0_21
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investigate the magnitude of the deviation of the profile angle depending on the value of rake angle and its effect on the strength of the pin-box connection.
2 Literature Review The distribution of stresses and contact pressures in threaded joints, especially drill pipe tool-joints, determines their static and fatigue strength, leak-tightness and resistance to self-loosening. The paper [1] proposes an analytical method based on the elastic mechanics. This is quite different from other papers, which mainly rely on finite element analysis. But the studies of the dependence of the connection strength on the accuracy of the profile angle are absent in it. In [2] a NC35 tool joint with double shoulder is considered as the research object and studied by finite element method (FEM) including von Mises stress field, contact stress and ultimate working torque of tool joint under different axial loads. Thread profile accuracy studies are not presented there. In [3], on the basis of Lame’s theory, the contact model of the joint thread is represented under different axial force, makeup torque and pressure difference between inner and outer pipe. The analysis software ANSYS\Workbench is applied to simulate the distribution of contact stress but without thread profile analysis. In [4] the stress distribution of the variable pitch casing joint have been calculated under tension, compression, bending load, and torque load and compared to stress distribution of the buttress casing thread. In [5] the process of pre-tightening of bolted joints (but not tapered thread) is simulated by 3D FEM. The torque–initial load relationship was obtained, and the effects of friction coefficient, pitch, Young’s modulus, assembly clearance and strain-hardening exponent were investigated. In [6], considering the contacting nonlinearity and material nonlinearity, three-dimensional finite element model of a certain type of premium connection is established with the consideration of helix angle. In [7] the influence of the external load, connection state and thread structure on the stress distribution in the thin-walled joint thread of a coring tool was analysed through simulations, from which the optimal thread structure was determined. At present, research on joint threads mainly focuses on oil drill strings which have a large wall thickness and a large thread design margin [8–10]. Wireline core drill strings are thin-walled structures that can be used as a reference for the thread design of core drilling tools but not for tapered thread tool-joints. Authors in [11] uses ANSYS software to carry out a 3D simulation of a ∅71 mm wireline core drill string and joint, and determined that the thread root had the highest stress but without depending on thread profile angle. Yin Feng [12] established a quasi-three-dimensional model for an ∅89 mm wireline core string joint under the condition of neglecting the influence of the helix angle. In paper [13] static mechanics to analyse the stress state of the negative angle thread of a ∅74 mm wireline core drill string and to calculate the torsional resistance of the thread is used. The contact stresses on the surfaces of the pin and box are determined depending on the size of the technological gap but not of the flank angle [14]. The mixed contact problem of the interaction of the cyclic-symmetric system of the collet nut blades with the inner bolt is solved [15] but not relatively tapered thread. The study [16] discusses the problem of deformation simulation of thread joint details and proposed easy measurement scheme but it does not includes stress, which is well discussed in [17, 18] but concerning coating thread surfaces. The investigation
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of the thread profile accuracy in tool joints is demonstrated in paper [19] but only from the point of view influence on contact pressures in oil and gas pipes. The studies of the tightness of the drill string connector depending on the tapered thread profile are shown in [20]. This paper does not include studies of the mechanical parameters of the tool-joint. Only the theoretical investigation of the tapered thread joint surface contact pressure in the dependence on the profile and the geometric parameters of the threading turning tool are demonstrated in [21].The lathe process of tapered thread producing is simulated in the research [22] which includes the investigation of the influence of the rake angle on the thread profile of the tubing connection and on the stress, fatigue safety factor and contact pressures. Therefore, the aim of the work is to do investigation of the stress, fatigue safety factor and contact pressure in the tool-joint thread in the dependence on the thread profile and the geometric parameters of the turning tool.
3 Research Methodology To ensure the accuracy of the tapered threads during manufacturing with lathe tool, it suggests the following: in the process of turning with a non-zero value of the rake angle, a convolute screw is formed. It means that not an Archimedean screw surface, which is actually regulated by the standard API spec 7–2, is received. The following expressions are the theoretical basis of the method of calculating of the convoluted screw axial profile: z(x) = tg(α)x
Pτ sin τ − , sin γ 2π
(1)
min where τ = γ − arcsin d2x sin γ , α is the flank angle (nominal value is α = 30°), P is the thread pitch, γ is the back rake angle, d min is the minimum thread diameter according to standard API spec 7–2. Since expression (1) is not algebraic but transcendent, it is necessary to predict the behaviour of the profile of the machined thread, i.e. with a given accuracy to obtain the coordinates of a given number of its points. Figure1 demonstrates the thread scheme according to the standard with the inclusion of the Cartesian coordinate system. The X-axis (mm) is directed radially, and the Z-axis (mm) is along the thread axis. So, it is quite obvious to accept such a curve as a straight line, and the half angle of the profile, that it forms, should in this case be calculated by the formulas: |za − zd | (2) αAD = arctg |xa − xd | |za − zb | αAB = arctg (3) |xa − xb | Research methodology in stress, fatigue safety factor and contact pressures is based on the FEM-modelling. The Abaqus/CAE 6.14 and Python-macro [23], developed by the authors, were used for modelling. The macro was used to automate the construction
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Fig. 1. Scheme of the standard tool-joint tapered thread with Cartesian coordinate system.
of a finite element model and obtain results. The fatigue safety factor D determines how much the load amplitude can be safely increased [24]. For uniaxial stress state. D=
σ−1 − ψσ σm . σa
(4)
where σ −1 is the endurance limit (MPa), σ a is the alternating stress (MPa), σ m is the mean stress (MPa), ψ σ is the mean stress sensitivity factor. For high-strength steels (σ t = 1150–1650 MPa), the value ψ σ = 0.33 can be taken. D · λa is the limiting amplitude. If D < 1, then the part will have limited fatigue life. For a multiaxial stress state, the values of the fatigue safety factor D according to the Sines’ criterion [25] can be calculated by the formula (4), in which: 1 (5) σa = (σa1 − σa2 )2 + (σa2 − σa3 )2 + (σa3 − σa1 )2 , 2 σm = σm1 + σm2 + σm1 = σmx + σmy + σmz , where σ ai is the alternating component of the principal stresses, σ ai = (σ i max− σ i min )/2; σ mi is the mean component of the principal stress, σ mi = (σ i max + σ i min )/2.
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4 Results We study the effect of deviations of the flank angleα of the pin thread on equivalent stresses and contact pressures in the drilling tool joints. Axisymmetric finite-element models of drilling tool joints ZN-80 and ZN-197 GOST 5286 with Z-66 and Z-152 GOST 28487 threads (2 3/8 REG and 6 5/8 REG API Spec. 7 equivalents) has been developed for this. The material of the parts is steel 40XH2MA (36 CrNiMo 4 equivalent) with a Young’s modulus E = 210 GPa, a Poisson’s ratio ν = 0.28, a yield strength σ y = 1080 MPa, a ultimate tensile strength σ t = 1200 MPa). Material plasticity and friction are simulated. The nonlinear section of the stress-strain diagram (σ-ε) is approximated by lines with points: (σ = 1080 MPa, ε = 0.0), (1129, 0.005), (1178, 0.014), (1228, 0.032), (1277, 0.062), (2087, 0.776).The following Abaqus/CAE parameters were used to create a contact model: sliding formulation – finite sliding, discretization method – surface to surface, gradually remove slave node overclosure during the step. Tangential Behavior: friction formulation – penalty, friction coefficient 0.05. Normal Behavior: pressure-overclosure – “hard” contact, allow separation after contact. Mesh parameters: deviation factor = 0.1, size = 2.6. Additionally, each edge of the contact surface was divided into 8 parts. The joint make-up was simulated by axial deformation of the box shoulder (Fig. 2(b)). At the upper end of the pin the pressure L acts, which simulates the external tensile load (Fig. 2(c)). For the approximate calculation of the fatigue safety factor D, the dependence of Sines (4, 5) with a material endurance limit of 400 MPa was used. We considered the fatigue loading cycle L min = 0 MPa, L max = 100 MPa. Joints with such values of the flank angle α of the pin thread were simulated: 30°, 30.1°, 29.9°. The α value was changed only for the loaded (short) flank of the pin thread (Fig. 2(a, b)). The flank angle of the box thread was not changed (30°). The results for α = 30° are shown in Fig. 2. After make-up, the highest stresses are localized in the area of the shoulder (Fig. 2(b, d)) and values reach the yield strength. For the ZN-80 joint, the stresses are large due to the smaller area of the shoulder. After tensile load, the highest stresses move to the area of the first loaded turn (Fig. 2(c, f)).The value α = 30.1° decreases the contact pressure CP at the shoulder, and the value α = 29.9° - increases it (Table 1). For small deviations of the flank angle (±0.1°), a change in the stress distribution is not visually noticeable, but a significant change in contact pressure values p on the loaded flank of the thread was found (Fig. 3). For a negative deviation (α = 29.9°), p values especially sharply increase in the point 9. Most of all, this is characteristic of the ZN-80 joint (Fig. 3(a, b)). In the ZN-197 joint, such deviations cause a sharp increase in p values at point 1. In addition, in this joint, negative and especially positive deviations more significantly reduces the D value in the area of the first loaded root of the pin thread (Table 1). Thus, negative deviations of the flank angle can cause deformation and damage of thread in flank areas. In the area of less loaded turns (located below) the irregularity of the contact pressure p can cause leakages. These studies correspond to the simulation results of ZN-80 joint with parameters σ y = 735 MPa, σ t = 882 MPa, = 0.2 mm, which also showed a negative effect from such negative deviations [26].
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Table 1. Values of the contact pressure at the shoulder CP and values of the fatigue safety factor D (D1 is in the first loaded root of the pin thread, Dmin is the minimum value in the pin) for different values of the loaded flank angle α of the pin thread α = 30°
α = 30.1°
α = 29.9°
CP (L = 0 MPa), MPa
1140
1110
1160
CP (L = 100 MPa), MPa
793
764
821
Tool joint
Output parameter
ZN-80 = 0.2 mm
ZN-197 = 0.3 mm
D1 = Dmin
−6.2
−6.4
−6.9
CP (L = 0 MPa), MPa
399
391
408
CP (L = 100 MPa), MPa
226
217
235
D1
−42
−58
−52
Dmin
−62.1
−69.4
−66.9
Fig. 2. Scheme of nodes numbering on the loaded flank of the pin thread (a) and distribution of the von Mises stress (Pa) in joints with nominal thread (b, c, d, f): b, c – ZN-80, = 0.2 mm; d, f – ZN-197, = 0.3 mm; b, d – L = 0 MPa; c, f – L = 100 MPa; A – pin; B – box.
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a
b
c
d
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Fig. 3. Values of the contact pressure p (MPa) on the first loaded flank of the pin thread in the points n (Fig. 2 (a)): a, b – ZN-80; c, d – ZN-197; a, c – L = 0 MPa; b, d – L = 100 MPa; ˛ – α = 30°; – α = 30.1°;▲ – α = 29.9°
Basing on the formulas (1,2,3) the Table 2, which illustrates dependence of the flank angle of the pin thread on the value of the rake angle of the tool, are obtained. The results are obtained for the thread Z-66. Table 2. Dependence of the flank angle of the pin thread on the value of the rake angle of the tool Flank angle
Back rake angle γ of the tool 0
5
8
10
−5
−8
−10
αad (loaded flank)
29,94
29,92
29,98
30,05
30, 16
30,36
30,52
αab (unloaded flank)
29,95
30,12
30,29
30,44
29, 95
30,02
30,11
The results show that in the case of using a thread tool with a non-zero value of the back rake angle, the flank angle increases to 30.5°.
5 Conclusion 1. In order to reduce contact pressures on thread flanks, negative deviations of the loaded flank angle of the pin thread should be avoided and positive should be preferred (on
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the condition that fatigue strength is ensured). In this regard, it is recommended to change the tolerance limits of this flank angle from (29.5°, 30.5°) to (30°, 30.5°) for the pin thread, and do not change the tolerance limits for the box thread. 2. In the case of using a thread cutter with a non-zero value of the back rake angle, the flank angle increases to 30.5°. 3. Therefore, the turning of the hard-to-machining steel thread can be done with the rake angle value −10° without changing the profile of the cutting carbide insert.
References 1. Xu, H., Shi, T., Zhang, Z., Shi, B.: Loading and contact stress analysis on the thread teeth in tubing and casing premium threaded connection. Math. Prob. Eng. 1, 287076 (2014). https:// doi.org/10.1155/2014/287076 2. Cheng, J., Sun, Y., Yongping, Y., Chen, L., Ma, X.: Nonlinear thermo-mechanical coupled analysis of high temperature effect on strength, contact stress and ultimate torque of tool joint. Int. J. Press. Vessels Pip. 188, 104221 (2020). https://doi.org/10.1016/j.ijpvp.2020.104221 3. Wang, Y., Xia, B., Wang, Z., Chai, C.: Model of a new joint thread for a drilling tool and its stress analysis used in a slim borehole. Mech. Sci. 7(2), 189–200 (2016). https://doi.org/10. 5194/ms-7-189-2016 4. Dong, L., Wang, J., Zhu, X.: Design and mechanical behavior study of ultrahigh-torque variable pitch casing joint. Adv. Mech. Eng. 11(1), 168781401881408 (2019). https://doi. org/10.1177/1687814018814084 5. Qingmin, Y., Zhou, H., Wang, L.: Finite element analysis of relationship between tightening torque and initial load of bolted connections. Adv. Mech. Eng. 7(5), 168781401558847 (2015). https://doi.org/10.1177/1687814015588477 6. Dou, Y., Li, Y., Cao, Y., Yang, Y., Zhang, J., Zhang, L.: FE simulation of sealing ability for premium connection based on ISO 13679 CAL IV tests. Int. J. Struct. Integrity 12(1), 138–148 (2020). https://doi.org/10.1108/IJSI-11-2019-0125 7. Wang, Y., Qian, C., Kong, L., Zhou, Q., Gong, J.: Design optimization for the thin-walled joint thread of a coring tool used for deep boreholes. Appl. Sci. 10(8), 2669 (2020). https:// doi.org/10.3390/app10082669 8. Dong, L., Zhu, X., Yang, D.: Study on mechanical behaviors of double shoulder drill pipe joint thread. Petroleum 5, 102–112 (2018) 9. Yosuke, O., Masaaki, S., Yoshinori, A., Taizo, M., Ryosuke, K., Daisuke, T., Masanobu, K.: Fretting fatigue on thread root of premium threaded connections. Tribol. Int. 108, 111–120 (2017) 10. Sorg, A., Utzinger, J., Seufert, B., Oechsner, M.: Fatigue life estimation of screws under multiaxial loading using a local approach. Int. J. Fatigue 104, 43–51 (2017) 11. Gao, J., Ma, Y., Wang, D., Ji, S.: Fatigue analysis on wire-line coring drill pipe joints in tonghua well-1 based on ansys workbench. Explor. Eng. Rock Soil Drill. Tunn. 44, 70–78 (2017) 12. Yin, F., Zhang, Y., Xiong, J., Xiong, L.: Simulation analysis on structural mechanism of the thread for wire-line drill pipe. Explor. Eng. Rock Soil Drill. Tunn. 41, 66–69 (2014) 13. Gao, S., Sun, J., Cai, J., Liu, D.: Calculation analysis on negative angle thread torque of wire-line coring drill pipe and test research. Explor. Eng. Rock Soil Drill. Tunn. 43, 45–49 (2016) 14. Shats’kyi, I.P., Lyskanych, O.M., Kornuta, V.A.: Combined deformation conditions for fatigue damage indicator and well-drilling tool joint. Strength Mater. 48, 469–472 (2016)
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15. Shatskyi, I., Ropyak, L., Velychkovych, A.: Model of contact interaction in threaded joint equipped with spring-loaded collet. Eng. Solid Mech. 8(4), 301–312 (2020) 16. Pryhorovska, T., Ropyak, L.: Machining error influnce on stress state of conical thread joint details. In: Proceedings of the International Conference on Advanced Optoelectronics and Lasers, vol. 9019544, pp. 493–497. IEEE (2019) 17. Shatskyi, I.P., Ropyak, L.Y., Makoviichuk, M.V.: Strength optimization of a two-layer coating for the particular local loading conditions. Strength Mater. 48(5), 726–730 (2016) 18. Shatskyi, I.P., Perepichka, V.V., Ropyak, L.Y.: On the influence of facing on strength of solids with surface defects. Metallofizikai Noveishie Tekhnologii 42(1), 69–76 (2020) 19. Onysko, O., Kopei, V., Pituley, L., Medvid, I., Lukan, T.: Influence of the thread profile accuracy on contact pressure in oil and gas pipes connectors. In: Ivanov, V., et al. (eds.) Advances in Design, Simulation and Manufacturing III. DSMIE 2020, Lecture Notes in Mechanical Engineering, pp. 432–441. Springer, Cham (2020). https://doi.org/10.1007/9783-030-50794-7_42 20. Onysko, O., Borushchak, L., Kopei, V., Lukan, T., Medvid, I., Vryukalo, V.: Computer studies of the tightness of the drill string connector depending on the profile of its tapered thread. In: Karabegovi´c, I., et al. (eds.) New Technologies, Development and Application III. NT 2020. Lecture Notes in Networks and Systems, vol. 128, pp. 720–729. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-46817-0_82 21. Onysko, O.R., Kopey, V.B., Panchuk, V.G.: Theoretical investigation of the tapered thread joint surface contact pressure in the dependence on the profile and the geometric parameters of the threading turning tool. IOP Conf. Ser. Mater. Sci. Eng. 749, 012007 (2020). https://doi. org/10.1088/1757-899X/749/1/012007 22. Kopei, V., Onysko, O., Panchuk, V.: The application of the uncorrected tool with a negative rake angle for tapered thread turning. In: Ivanov, V., et al. (eds.) Advances in Design, Simulation and Manufacturing II. DSMIE 2019, Lecture Notes in Mechanical Engineering, pp. 149–158. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-22365-6_15 23. vkopey/ThreadsAbaqus: Abaqus/CAE python scripts for modelling threaded connections of oil and gas equipment. https://github.com/vkopey/ThreadsAbaqus 24. Serensen, S.V., Kogaev, V.P., Shneiderovich, R.M.: Bearing Capacity and Strength Calculations of Machine Parts. Mashinostroenie, Moscow (1975). in Russian 25. Sines, G., Waisman, J.L. (eds.): Behavior of Metals Under Complex Static and Alternating Stresses Metal Fatigue, pp. 145–169. McGraw-Hill, New York (1959) 26. Kopey, V.B., Onysko, O.R., Panchuk, V.G.: Computerized system based on Free CAD for geometric simulation of the oil and gas equipment thread turning. IOP Conf. Ser. Mater. Sci. Eng. 477(1), 012032 (2019). https://doi.org/10.1088/1757-899X/477/1/012032
Structure and Strength Properties of Al-Cr Alloys Obtained by Quenching from a Liquid State and Laser Surface Reflow Aleksandr B. Lysenko1(B) , Tatyana V. Kalinina1 , Sergei V. Gubarev1 , Iryna V. Zagorulko2 , and Yana V. Vishnevskaya1 1 Dniprovsk State Technical University, Kamenskoe, Ukraine
[email protected] 2 Institute of Metal Physics named after G.V., Kurdyumov of National Academy of
Sciences of Ukraine, Kiev, Ukraine
Abstract. Complex studies of the structure and strength properties of Al-Cr alloys prepared in the shape of ribbons with a thickness of l = (30–80) μm by rolling a melt jet in steel rolls as well as by reflow the surface of massive samples to a depth of h≈l with millisecond laser pulses, have been carried out. It is shown that anomalously supersaturated solid solutions based on Al (α) which retain the initial concentration of alloys, are recorded in rapid-quenched ribbons with a content of up to 7% Cr (*). In the zone of laser reflow the maximum saturation of the α-solution does not exceed ~3.2% Cr. Outside the areas of formation of strongly supersaturated solid solutions in the structure of ribbons and layers that are reflowed by a laser, dispersed mixtures of a depleted α-solution with initial crystals of Al7 Cr equilibrium intermetallic, the sizes of which increase with increasing in chromium concentration, are formed. Structural changes observed in rapid-quenched ribbons and laser-reflowed layers are accompanied by significant strengthening of Al-Cr alloys. The maximum value of σf ≈ 400 MPa is recorded in ribbons with a content of 9.2% Cr that have the structure of a dispersed conglomerate of phases. This value is 3.5 times higher than the strength of the molten samples with corresponding composition. In the analytical block of the work it was found that the lesser tendency of Al-Cr alloys to form strongly supersaturated solid solutions under conditions of fast laser quenching is due to the peculiarities of crystallization of the reflowed zone. In its lower part from the reflowing boundary matrix crystals of an α-solution with a Cr content close to equilibrium grow. In the upper horizons of the laser bath the formation of solid solutions of the initial composition is obstructed due to the enrichment of the melt with chromium as well as the slowing down of the cooling process due to the release of latent heat of transformation at the growth front of the matrix crystals of the α-solution. Keywords: Rapid quenching · Laser reflow · Strength properties · Cooling rate · Crystallization mechanisms
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 186–196, 2021. https://doi.org/10.1007/978-3-030-75275-0_22
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1 Introduction As it is known most of the physical and mechanical characteristics of materials depend on their structure that is formed under the influence of compositional (nature and concentration of components) and technological (smelting and further processing modes) factors. In the list of technological variables the most important place is occupied by the cooling rate υ at the stage of the melt solidification with the formation of an initial microstructure. At the values of υ above 104 K/s morphological changes in the microstructure occur in the alloys; solid solutions, which are supersaturated in comparison with the equilibrium state, and metastable crystalline and amorphous phases [1–3], which have a beneficial effect on complexes of demanded properties, are formed. Record high cooling rates up to ~1010 K/s are achieved using liquid quenching (LQ) methods based on the mechanism of heat removal from thin melt layers into massive heat receivers. A similar principle of rapid cooling of melts also takes place when the surface of materials is reflowed by highly concentrated energy flows, in particular, by laser radiation [4–6]. Distinctive features of the technology of laser surface reflow (LSR) are perfect thermal contact between the melt and the processed material, the identity of the chemical content of the rerflowed layer and the laser target areas located under it, as well as the presence of equilibrium structural components at the reflow boundary that have increased competitiveness in comparison with metastable phases when laser bath solidifying. These factors leave an imprint on both the dynamic regime [7] and the kinetics of crystallization of melts [8–10] under conditions of laser rapid quenching. This indicates the relevance of comparative studies of the heat transfer processes and formation of the structure that are implemented in the technologies of LQ and LSR. Using response surface methodology (RSM) in optimization of processing technology for differents materials is given in papers [11, 12]. In this work we studied the structure and strength properties of the Al-Cr alloys prepared by two alternative methods of rapid cooling from the liquid state. The research program was focused on obtaining experimental evidence and theoretical substantiation of the effect of the lesser tendency of alloys to form metastable strongly supersaturated solid solutions under LSR conditions.
2 Experimental Methogology The studies were carried out on samples of Al-Cr alloys with different (0–10)% content of transition metal. The alloys were prepared from components with a purity of at least 99.9% in graphite crucibles in a Tamman furnace. The composition of the obtained alloys was controlled by comparing the total mass of the components and ingots as well as selectively by energy-dispersive analysis using REM-106I electron microscope. Rapidly quenched samples in the shape of ribbons with a thickness of l = (30–80) μm were obtained by rolling of a melt jet in steel rolls. The cooling rate of the ribbons υLQ was estimated by the values of l using the methodology of work [13]. The operation of laser surface reflow of the samples cut from ingots was carried out on a GOS-1001 pulsed installation in the free generation mode with a pulse duration of τ≈10–3 s. Different depths h of the reflowed zone were obtained by varying the power
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density q of laser radiation due to changes in the energy of the pump of laser and the area of the focusing spot of the laser beam on the working surface of the samples. The cooling rate of the laser microbath of the melt υLSR was calculated using the algorithm described in detail in the works [7, 9]. The microstructural studies of the rapidly quenched ribbons and the zone of laser reflow of Al-Cr alloys were performed on a NEOPHOT-32 metallographic microscope. The phase composition of the samples under study was determined by decoding the X-ray diffraction patterns that were obtained on a DRON-3 diffractometer in monochromatic CuKα radiation. The saturation of solid solutions of chromium in aluminum (α) was monitored by the values of the periods of a crystal lattice by comparing them with the linear dependence a (% Cr) corresponding to single-phase structures of α-solution. The tensile strength σf was determined using segments of rapidly quenched ribbons with 20 mm length and 2 mm width. The thickness of the samples at the rupture point was determined using IZV-1 optical small displacement meter with accuracy of ±1 μm. The values of the microhardness Hμ were measured using a PMT-3 device at a load of 20 g.
3 Research Results According to the data of previous studies [14, 15], an indispensable element of the microstructure of rapid-quenched Al-Cr alloys with a chromium content of up to 10% is a solid α-solution based on aluminum. The saturation of the α-solution depends on the concentration of the alloying element and the rate of the LQ process. At melt cooling rates that exceed ~105 K/s in a certain concentration range anomalously oversaturated αsolutions are recorded, in the lattice of which a much larger relative amount of chromium dissolves than in the equilibrium state (0.72% [16]). If the entire alloying element is located in the base metal lattice, the single-phase α-solution structures are formed. For these structures the concentration dependence of the a crystal lattice period a (% Cr) is linear. Consequently, it can play the role of a “calibration” straight line that allows determining the concentration of the alloying element in the solid solution from the experimental values of a. In Fig. 1, the dashed line 1 shows the dependence a (% Cr) obtained by processing Xray diffraction patterns from rapidly quenched ribbons of Al-Cr alloys with a thickness of l = 25–30 μm that corresponds to the value of υLQ ≈2 × 106 K/s. As can be seen, while quenching Al-Cr alloys from the liquid state at rates exceeding 106 K/s, anomalously supersaturated solid solutions with an initial chromium content are formed in a fairly wide (up to about 7% of Cr) concentration range. In addition to the linear graph of a(% Cr) for LQ samples, there are shown similar dependences corresponding to the structures of the area of single (curve 2) and threefold (curve 3) reflow of Al-Cr alloys by laser pulses with a duration of ~10–3 s (Fig. 1). The analysis of curve 2 shows that in the area of low (up to ~1.5%) chromium concentrations nearly linear decrease in the lattice period of the α-solution is observed. Within this concentration range the numerical values almost coincide with the “calibration” straight line that indicates the formation of supersaturated solid solutions with initial chromium content in the layers melted by the laser.
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Fig. 1. Concentration dependences of the lattice period of the solid solution of Cr in Al for Al-Cr alloys obtained by LQ (1) and LSR methods (2, 3): 2 – single reflow, 3 – threefold reflow
With concentration of Cr increasing over 1.5%, the dependence 2 loses its linear character and deviates more and more from the dashed line 1. The minimum value a = 0,4042 nm is achieved in the alloy containing 3.7% of Cr. Comparing the given value of a with straight line 1, it can be shown that the maximum saturation of the α-solution in Al-Cr alloys singly reflowed with a laser is 1.9% of Cr. The latest result leads to the conclusion that under the considered conditions of laser surface processing the supersaturated solid solutions are recorded. The concentration limit of chromium in obtained supersaturated solid solutions is significantly lower than the values that are typical for rapid-quenched ribbons. One of the possible reasons of the revealed effect may be that during the duration of the laser pulse rather coarse inclusions of high-chromium excess phase that are present in the structure of molten Al-Cr alloys do not have time to completely dissolve in the laser bath. As a result, the concentration of the alloying element in the liquid solution does not reach the initial alloy composition and, consequently, the α-solution formed in the laser reflow area will also be less saturated. In order to check the latest assumption, the Al-Cr alloy ingots were subjected to repeated laser reflow with the control of the value of the solid solution lattice period after each irradiation cycle. It was found that in alloys with the content of (1.5–4.0)% chromium with increasing in the processing number n from 1 to 3 a regular decrease in the values (that approach to dependence of 1) of a is observed. With increasing in the number of surface reflows over three the value of a remains almost the same that indicates the constancy of the concentration of the solid solution of Cr in Al. The minimum value a = 0.4038 nm that is recorded in threefold reflowed samples of Al-Cr alloy corresponds to α-solution concentration of ~3.2% of Cr that is 1.7 times higher than the level of limiting
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solubility of chromium in aluminum at n = 1. Despite this, the maximum saturation of the α-solution with chromium in the area reflowed by the laser is much lower than the value of ~7% of Cr that is typically for rapidly quenched ribbons. A combination of X-ray phase and metallographic analysis methods was used to study the changes in the structural-phase state of the LQ products and the laser reflow area that are revealed as the chromium concentration in the alloys increases. It is shown that a single-phase cellular structure of the solid solution of the initial chemical composition is fixed in the plane of laser treatment at the concentration ranges of the linear decreasing in the lattice period of the α-solution. In the range where the values of a decrease deviating from straight line 1, amicrostructure is formed. It consists of solid solution cells and dispersed secondary precipitates of the equilibrium Al7 Cr intermetallic, the density of which rises with increasing in the content of the transition metal. In alloys corresponding to the ascending branches of the a (% Cr) dependence, the quasi-eutectic mixtures of initial Al7 Cr crystals and a solid solution are formed. In the structures of this type the saturation of the α-phase varies from the values that are limiting for laser technology to the equilibrium concentration corresponding to the state diagram of the Al-Cr system. Finally, in alloys containing more than ~9% Cr, in addition to a quasi-eutectic mixture of a depleted solid solution and an excess phase, coarse initial crystals of the Al7 Cr compound are metallographically revealed. Structural changes caused by the processes of LQ and LSR causes the significant strengthening of Al-Cr alloys. This is evidenced by the concentration dependences of the ultimate strength and microhardness of rapidly quenched ribbons and the region of re-solidification of the laser bath shown in Fig. 2 and 3. As can be seen from Fig. 2, in the concentration range of the formation of a single-phase structure of a supersaturated α-solution the values of σf and Hμ increase almost linearly. In particular, the specific increase in microhardness per weight percent of chromium is approximately 72 MPa. The hardening effect due to the formation of an ultrafine conglomerate of phases is more significant. The corresponding specific characteristic increases to 118 MPa. With an increase in the chromium concentration over 8% the rate of LQ-samples hardening slows down that is explained by some coarsening of excess Al7 Cr crystals. Further coarsening of the microstructure causes oppositely directed changes in the ultimate strength and hardness: the values of σf begin to decrease, while the dependences Hμ (% Cr) show only a slight decrease in the increase in microhardness. The maximum of σf (% Cr) dependence is achieved in rapidly quenched ribbons containing ~9.2% Cr. According to the data of quantitative metallographic analysis, these ribbons have heterophase structures, in which particles of chromium aluminide Al7 Cr with approximate dimensions of (0.2–0.4)·10–6 m are located at the distances of (1–2) 10–6 m with an average density of ~4·1011 m−2 in the plane of observation. The maximum value of σf is about 400 MPa that is approximately 3.5 times higher than the strength of cast alloys of the corresponding compositions. Figure 3 illustrated the Hμ (% Cr) dependence obtained by averaging the results of ten durometric measurements performed in the diametrical directions of the laser reflow area on samples with different chromium content. As can be seen, it is qualitatively similar to the analogous dependence for rapidly quenched ribbons (Fig. 2 and 3) and confirms the existence of interconnection between
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Fig. 2. Dependences of the ultimate strength (1) and microhardness (2) on the chromium content for rapid-quenched ribbons of Al-Cr alloys with a thickness of (40–50) μm
Fig. 3. Graphs of the distribution of the averaged values of Hμ for laser-reflowed Al-Cr alloys depending on the chromium content (1) and the distance from the laser processing plane (2) for the Al-4% Cr alloy
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the nature of changes in microhardness in different concentration ranges and the structure of laser-reflowed alloys of the corresponding compositions. Indeed, on the Hμ (% Cr) graph a region of changes in microhardness, which are close to linear one, can be distinguished; it correlates with the interval of anomalously supersaturated solid solutions formation. The length of the initial linear region on the Hμ (% Cr) dependence for alloys that have undergone laser-pulse reflow is noticeably smaller than the corresponding interval observed in rapidly quenched ribbons; that agrees with the above-mentioned ratio of the limiting saturation of the α-solution for the samples prepared by two analyzed methods of quenching from liquid states. Also the regions of accelerated and delayed changes that correspond to heterophase structures with different relative amounts and dimensions of crystals of Al7 Cr chromium aluminide are quite clearly distinguished in Hμ value. From a comparison of the results of durometric studies of rapidly quenched Al-Cr alloys obtained by the LQ and LSR methods it can be concluded that the absolute values of Hμ of the laser reflow area noticeably exceed the microhardness of a ribbon made by rolling of a melt jet in rolls. Hence, a lower level of solid solution hardening in laser-reflowed samples is more than compensated for by the effect of their hardening by dispersed precipitates of the excess phase of Al7 Cr. The hardness distribution graphs in a normal section of laser-reflowed area (Fig. 2 and 3) show that the Hμ values obtained by measurements in the processing plane are inherent only in the near-surface layers with a thickness of d ≈ (15–30) μm. With increasing pressure it begins to decrease noticeably and at the reflowing boundary it reaches a level of ~200 MPa that is typically for α-solid solution with an equilibrium content of transition metal. Such a course of Hμ (d) dependences is an indirect sign of the distribution of chromium that is mainly accumulated in the upper horizons of the reflowed layer.
4 Discussion of the Results One of the results of the carried out experimental studies that requires a special physical interpretation is significantly lower limiting saturation of the solid solution of chromium in aluminum that is fixed at re-solidification of the area reflowed by the laser, in comparison with the α-solution formed under conditions of rapid cooling of thin layers of the melt on a quenching device. Possible reasons of the revealed effect can be either the corresponding ratio of the cooling rates (υLSR < υLQ ) of melt layers of comparable thickness (h ≈ l), or kinetic difficulties in the formation of metastable crystalline phases during solidification of the area reflowed by the laser. To analyze the first of the mentioned factors using computational algorithms [9, 11], we calculated υLQ and υLSR dynamic parameters depending on the thickness l of the rapidly quenched ribbons and the depth h of the laser melt bath. The calculation results in logarithmic coordinates are shown in Fig. 4. The nature of the mutual location of the analyzed graphs indicates that in the entire specified range of variation of technological variables l and h (from 50 to 500 μm) the cooling rate of laser bath υLSR is significantly higher than the rate of quenching melt layers υLQ on the heat receiving blocks. At the lower boundary of this interval the ratio
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Fig. 4. Dependences of the cooling rate on the melt layers thickness for the traditional LQ methods (1) and LSR method (2) calculated by the algorithms of [11] and [9], respectively
υLSR /υLQ is equal to five, and in layers of maximum thickness (500 μm) it increases to 25. The most probable reason for the observed ratio of the cooling rates υLSR > υLQ is the fact that in laser technology at the reflowing boundary perfect thermal contact between the melt and the regions of the laser target with the initial structure is formed, while in LQ methods the rate of heat removal from the melt to the substrate is limited by the finite value of the heat transfer coefficient. The results of the performed calculations lead to the conclusion that LSR method has significant dynamic advantages, and therefore, higher potentialities for the formation of metastable structural states in alloys, including anomalously supersaturated solid solutions, in comparison with traditional methods of melt quenching. However, in reality these advantages are not reflected in the degree of metastability of the structure of laserreflowed surface layers. This indicates that the kinetic factor plays a dominant role in the processes of structure formation and requires a detailed analysis of the successive stages of crystallization that develop during the transition to the supercooled state of various areas of the laser bath. For this purpose the cooling curves were calculated for the surface (1), central (2), and adjacent to the reflow boundary (3) areas of the reflowed layer. The calculations were carried out with respect to a massive Al-plate that was irradiated with laser pulses of duration of τ = 0.95·10–3 s at a radiation power density of q = 109 W/m2 . As can be seen from Fig. 5, after the end of the action of the laser pulse, first of all area 3 passes into the supercooled state (T < Tm ); at this boundary there are partially reflowed crystals of the matrix phases that are capable of growth.
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Consequently, the crystallization of the laser bath begins precisely in this area, and only after some time intervals it becomes possible in the central (2) and surface (1) areas. It is logical to suppose that the most competitive mechanism of the crystallization of near-boundary area 3 is the growth of crystals of the α-solution with close to equilibrium chromium content from the bottom of the bath in the direction of heat transfer. In the process of their rapid moving deep into the melt, the area of preferably oriented dendrites or columnar crystals is formed. In this case, the excess amount of the transition metal is partially captured by crystal front; as a result, the saturation of the solid solution increases. The part of the alloying element that was not included in the α-solution is pushed aside into the upper horizons of the bath causing the phenomenon of zonal segregation.
i tm – time to reach the melting point of aluminum by Тm=933К і – area of the laser bath Fig. 5. Calculated dependences T (t) for surface (1), central (2) and near-boundary (3) areas of the laser bath formed as a result of irradiation of the Al-plate with laser pulses with a duration of τ = 0.95 10–3 s at a power density of radiation of q = 109 W/m2 (a)
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Change in the sequence of transition of different areas of the laser bath to the supercooled state due to the release of latent heat of transformation at the growth front of matrix crystals (b). Turning to the thermal aspect of the laser bath crystallization, we note that as a result of the release of the latent heat of transformation, the temperature of the melt in crystallization front of the α-solution increases that slows down the cooling of the upper part of the reflowed layer. This effect is developed to the greatest extent in the central area 2, as a result, after the near-border area 3, not area 2, but area 1 passes into a supercooled state as it is shown in the inset to Fig. 5. In this case, for a certain period of time, the growth of columnar crystals of the solid solution from area 3 to area 2, which has an increased (T > T m ) temperature, becomes impossible. Under these conditions the movement of the α-solution crystals front is suspended and the crystallization of the supercooled surface area 1 begins. This process is carried out by the nucleation and growth of phases, the nature of which depends on the composition of the melt, the cooling rate, and a number of other factors. It can be expected that at a low (up to 2%) chromium concentration in the alloy, area 1 will solidify with the formation of a supersaturated solid solution of the initial composition. In the alloys containing (2–3)% Cr the cooling rate of the laser bath does not ensure the retention of the entire amount of the alloying element in the solid solution. That is why after the finishing of the crystallization of surface area 1, the initial stage of the decomposition of the saturated solid solution develops; it is accompanied by the appearance of secondary precipitates of the Al7 Cr phase in the structure. In alloys containing more than 4% Cr at the crystallization of the surface regions of laser bath, twophase structures of the quasi-eutectic type, consisting a depleted α-solution and particles of the Al7 Cr intermetallic compound, the sizes of which increase with increasing in the alloying element concentration, are formed. In accordance with the proposed model, the central area 2 solidifies the last. Its structure is formed under the influence of two alternative mechanisms: the growth of matrix crystals from the bottom of the bath and one of the structure formation processes that are realized in the surface area and is considered above. As a result, the central regions of the layers reflowed by the laser solidify the last with the formation of a structure that is typical for areas 3 or 1, or a combination thereof.
5 Conclusions Summarizing the results of the performed analysis, we can come to the conclusion that the lower tendency of laser-reflowed Al-Cr alloys to form metastable anomalously supersaturated solid solutions in comparison with the products of LQ is due to two main reasons: – participation in crystallization processes of matrix equilibrium phases that initiate the formation of the area of the α-solution columnar crystals with a close to equilibrium chromium content in the lower part of the reflowed layer; – a significant decrease in the cooling rate of the upper horizons of the laser bath due to the release of latent heat of transformation in the process of directional crystallization of the near-border area 3.
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References 1. Miroshnichenko, I.S.: Quenching from a liquid state. Metallurgy, Moscow,SSSR (1982). (in Russian) 2. Filonov, M.R., Anikin, Yu.A., Levin, Y.B.: Theoretical foundations of the production of amorphous and nanocrystalline alloys by ultrafast quenching. MISIS, Moscow, Russia (2006). (in Russian) 3. Herlach, D., Galenko, P., Holland-Moritz, D.: Metastable solids from undercooled melts. Elsevier, Amsterdam. (2007). https://doi.org/10.4028/www.scientific.net/MSF.539-543.1977 4. Kovalenko, V.S. (editor). Handbook of laser processing technology. Technics, Kiev, Ukraine (1985). (in Russian) 5. Grigoryants, A.G., Safonov, A.N.: Surface laser processing methods. M.: Higher School, Moscow, SSSR. (1987) (in Russian) 6. Uglov, A.A.: State and prospects of laser technology. Phys. Chem. Mater. Process. 4, 32–42 (1992) 7. Lysenko, A.B., Korovina, N.A., Brekhara, G.P.: Influence of technological factors on the dynamics of thermal processes in the area of metal reflowed by laser radiation. Math. Model. 2(7), 99–103 (2001) 8. Lysenko, A.B., Korovina, N.A., Pavluchenkov, I.A.: Metal crystallization kinetics in conditions of laser rapid hardening. In: Laser Technologies in Welding and Materials Processing. E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine (2005) 9. Lysenko, A.B., Korovina, N.A., Yakunin, E.A., et al.: Features of heat transfer and crystallization in laser processing of alloys with surface reflow. Metal Phys. Latest Technol. 27(11), 1503–1518 (2005). (in Russian) 10. Lysenko, A.B., Lysenko, A.A., Korovina, N.A., Kravets, O.L., Gubarev, S.V.: Structure and properties of glassy alloys subjected to laser surface melting. Phys. Chem. Mater. Process. 3, 81–88 (2008). (in Russian) 11. Burya, A. I., Ye, A., Yeriomina, V.I., Volokh, P. D.: Study of the effect of transducer thickness and direction on the coercive force magnitude. In: Karabegovi´c, I. (ed.) New Technologies, Development and Application II, pp. 229–237. Springer, Cham (2020). https://doi.org/10. 1007/978-3-030-18072-0_26 12. Kalinichenko, S.V., Ye, A., Yeriomina, A. I., Burya, P. D.: Optimization of polychlorotrifluoroethylene processing technology by the response surface methodology. In: Karabegovi´c, I. (ed.) New Technologies, Development and Application III, pp. 322–330. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-46817-0_37 13. Lysenko, A.B., Borisova, G.V., Kravets, O.L.: Calculation of the cooling rate when quenching alloys from a liquid state. Phys. Technol. High Pressures 14(1), 44–53 (2004). (in Russian) 14. Yakunin, A.A., Silka, L.F., Lysenko, A.B.: Structure and properties of rapidly crystallized and extruded Al-Cr alloys. Phys. Met. Met. Sci. 56(5), 945–950 (1983). (in Russian) 15. Lysenko, O.B., Kalinina, T.V., Zagorulko, I.V., Vlasova, Y.M.: The structure and power of aluminum alloys with transition metals, which are removed by rolling the jet to melt at the rolls. In: Collection of Scientific Papers of DDTU, Thematic issue Machines and Plastic Deformation of Metal. DDTU, Kamyanske, Ukraine, pp. 253–258 (2018) (in Ukrainian) 16. Hansen, M., Anderko, K.: Structures of double alloys. M.: Metallurgizdat, Moscow, SSSR (1962) (in Russian)
Simulation of the Operating Modes of the Proposed Equipment When Loading the External Circuit of the Working Hydraulics in Tractor ˇ Juraj Jablonický, Peter Kožuch(B) , Lubomír Hujo, Romana Janoušková, and Matej Michalídes Faculty of Engineering, Department of Transport and Handling, Slovak University of Agriculture, Tr. A. Hlinku 2, 949 76 Nitra, Slovak Republic [email protected]
Abstract. The aim of the presented article is to verify the automatic and manual operating mode of the proposed measuring device for loading the external circuit of the working hydraulics of the tractor in the simulation program FluidSim. Before starting the simulation, it is necessary to select the individual parameters of the tested hydrogenerator UD 20, which is specified by the manufacturer, and to create a simulation model of this device according to the design. The device allows measurements to be made in automated mode by means of an electrohydraulic proportional valve and in manual mode by means of a throttle valve. In the simulations in both operating modes, the flow rates at increasing speeds and constant pressures from the simulations were compared with the data provided by the hydrogenerator manufacturer. By comparing the data, it is possible to see negligible percentage differences, which are caused by the increasing temperature of the working fluid and the internal resistance of the hydrostatic transducer and filter. From these findings it follows that the proposed electromechanical device meets all the specified requirements and during real operational tests of the tractor hydraulics, its function will be correct. Keywords: Hydrogenerator · Flow characteristic · Simulation · Tractor · Hydraulics
1 Introduction Mechanization in agriculture and related activities are constantly advancing, resulting in improvements and the development of new hydraulic systems or components that are part of the working hydraulics of the tractor, as well as other working machines such as handling and forestry. The development and improvement of hydraulic systems would not be possible without quality research in the field. Current agricultural machinery and equipment is at a high technical level, which means that even measuring and diagnostic technology must meet adequate requirements for the technical level and sophistication of agricultural machinery [1–4]. In the past, with a lower level of electronization of © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 197–204, 2021. https://doi.org/10.1007/978-3-030-75275-0_23
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hydraulic systems of agricultural technology, simpler and less demanding measuring devices were sufficient to perform either laboratory or operational tests of hydraulic systems. With the growing trend of development of hydraulic systems, it is necessary to improve the measuring technique. Current measuring devices use a high degree of electronization and automation, not only for measuring, but also for recording and evaluating measured values [5]. These devices are subject to ever-increasing requirements, especially in recording data online or in databases for more time-consuming tests of hydraulic systems, repeatability of measurements and elimination of inaccuracies, or errors in the measurement of hydraulic systems [6–8].
2 Simulation Model of Measuring Device Before performing simulation processes in manual as well as automated loading mode, it was necessary to enter the characteristics of individual components and hydraulic fluid in accordance with the technical specifications into the simulation program. The simulation process of loading the external circuit of the tractor ’s working hydraulics can be performed in two modes in accordance with the design of the electromechanical loading device. Both simulation processes must be able to assess the safety function of the safety valve on the external circuits of the tractor’s working hydraulics when it is loaded above the permissible pressure value in our case above 20 MPa. They must also be able to measure the nominal value of the hydrogenerator flow with the required accuracy. In the event of a fault in the safety valve on the external circuit of the tractor’s working hydraulics, the device must be secured against damage by its own safety valve, which is set to the maximum permissible pressure value of 20 MPa.The operation of the proposed electro-mechanical device for loading the external circuit of the working hydraulics of the tractor was verified in the simulation program FluidSIM. Based on the design of the loading device, a simulation model of the tested device was compiled.The model shown in Fig. 1 consists of the following parts: • simulation model of the external circuit of the working hydraulics of the tractor, • simulation model of the electro-mechanical device for loading the external circuit of the working hydraulics of the tractor, • electrical control circuit of the electro-hydraulic proportional valve. The simulation model of the external circuit of the working hydraulics of the tractor consists of a hydrogenerator connected to the drive, which is secured against overload by a safety valve, which is set to a pressure of 20 MPa. The setting of the maximum working pressure of 20 MPa is based on the real conditions under which the hydraulic system of the tractor works. Several authors [9–11] deal with the dependences of working pressure and flow of a hydrogenerator during tests of hydraulic transducers in agricultural tractors. The above simulation model consists of all the components shown and described in Fig. 1, but is supplemented by another digital flow meter, which is included in the return line. As stated [10] electro-hydraulic proportional valve is used to create a simulated load is controlled by an electrical circuit, whose software and hardware was solved in cooperation with the Department of Electrical Engineering, Automation and Informatics, Faculty of Technology, Slovak University of Agriculture in Nitra.
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Fig. 1. Model of simulation of loading of external circuit of working hydraulics of tractor
2.1 Manual Mode Simulation When simulating the manual load mode of the tractor’s external working hydraulic circuit, the three-way valve is switched so that hydraulic fluid flows from the tractor’s external working hydraulic circuit towards the throttle valve, as shown in Fig. 2. Manual mode also serves to heat the hydraulic fluid to operating temperature. Several authors [12, 13] deal with the evaluation of hydraulic fluids depending on temperature and pressure. Both authors found that operating parameters, especially temperature and pressure, affect the working fluid and subsequent measurements. To verify the simulation in manual mode, in Table 1 shows the recorded flow values at increasing hydrogenerator speeds, which are compared with the flow values given by the hydrogenerator manufacturer. Flow is important to monitor with regard to the assessment of the technical condition of the monitored hydrogenerator [14]. The flow values were determined at no load and the differences in the simulation values and the manufacturer’s values are due to the increasing temperature of the working fluid and the pressure recorded during the simulation and is caused only by the internal resistance of the hydrostatic transducer, filter and piping. The negative difference in the compared flow values is caused by the temperature of the working fluid which affects the viscosity of the working fluid used.
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Fig. 2. Simulation of the load of the external circuit of the working hydraulics of the tractor manual mode Table 1. Comparison of values from the simulationin manual mode Speed, nHG, min-1
Hydrogenerator flow, QHGV, dm3/rpm
Flow during simulation, QHGS, dm3/rpm
Difference, %
500
9.92
10.12
−1.97
750
14.88
15.09
−1.39
1000
19.84
20.02
−0.90
1250
24.80
24.89
−0.36
1500
29.75
29.72
0.10
1750
34.71
34.50
0.84
2000
39.67
39.23
1.10
2250
44.63
43.92
1.60
2500
49.59
48.56
2.08
2750
54.55
53.17
2.53
3000
59.51
57.73
2.99
3200
63.48
61.35
3.36
2.2 Automatic Mode Simulation In the simulation in the automated loading mode of the tractor’s external working hydraulic circuit, the three-way valve is switched so that hydraulic fluid flows from the
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tractor’s external working hydraulic circuit towards the electro-hydraulic proportional valve as shown in Fig. 3.
Fig. 3. Simulation of the load of the external circuit of the working hydraulics of the tractor -automatic mode
To verify the simulation in automated mode, in Table 2 shows the recorded flow values at increasing hydrogenerator speeds, which are compared with the flow values given by the hydrogenerator manufacturer. The flow values were determined at no load and the differences in the simulation values and the manufacturer’s values are caused by the increasing temperature of the working fluid and the pressure recorded during the simulation and is caused only by the internal resistance of the hydrostatic transducer, filter and piping. The negative difference in the compared flow values is caused by the temperature of the working fluid which affects the viscosity of the used working fluid. Based on the specified requirements, this proposed device can be used in long-term tests focused on the effect of used hydraulic fluids on the wear of elements in the hydraulic system depending on their flow characteristics, as well as to monitor the contamination of applied hydraulic fluids in the hydraulic operating circuit. Several authors [15–17] state that the pollution of the used liquid has a great influence on the operation of the device. At the same time, according to the author [18] the physico-chemical composition of the used hydraulic fluid also has an effect on the wear of the elements. The main advantage of this technical solution is the possibility of simulating the operating load of hydraulic systems of agricultural, forestry and handling equipment through an electrohydraulic proportional valve and ensuring the repeatability of tests in scientific research.
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Speed, nHG, min-1
Hydrogenerator flow, QHGV, dm3/rpm
Flow during simulation, QHGS, dm3/rpm
Difference, %
500
9.92
10.13
−2.07
750
14.88
15.12
−1.59
1000
19.84
20.07
−1.15
1250
24.80
24.97
−0.68
1500
29.75
29.80
0.17
1750
34.71
34.64
0.20
2000
39.67
39.41
0.66
2250
44.63
44.15
1.08
2500
49.59
48.58
2.04
2750
54.55
53.41
2.09
3000
59.51
58.14
2.30
3200
63.48
61.81
2.63
3 Conclusion The development of hydraulic systems is constantly advancing and hydraulic systems are characterized by a high degree of precision in production. For these reasons, the precise engineering production of individual elements of the hydraulic circuit is important, where it is important to monitor the accuracy of CNC machine tools using new methods and trends [19–21]. Therefore, it is important to introduce and use more accurate measuring techniques in testing the tractor hydraulics. When comparing the flow values from the FluidSim simulation program and the values given by the manufacturer in both operating modes, it can be seen. These differences are caused by the increasing temperature of the working fluid, which affects the viscosity of the fluid used, as well as the increase in pressure caused by the internal resistance of the hydrostatic transducer, particulate filter and piping. The percentage differences between the compared flow rates from the simulation and the flow rates from the manufacturer are negligibly small and it can be argued that, based on the specified requirements, the designed equipment can be measured with sufficient accuracy during in-service tests. Acknowledgements. This publication was supported by the Operational Program Integrated Infrastructure within the project: Demand-driven research for the sustainable and inovative food, Drive4SIFood 313011V336, cofinanced by the European Regional Development Fund. This work was supported by project VEGA 1/0155/18 “Applied research of the use of ecological energy carriers in agricultural, forestry and transport technology.” This work was supported by project KEGA 028SPU-4/2019 “Practical utilization of design and testing knowledge of transmission systems of hydraulic mechanisms of mobile agricultural and forestry machinery.”
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References 1. Simiki´c, M., Dedovi´c, N., Savin, L., Tomi´c, M., Ponjiˇcan, O.: Power delivery efficiency of a wheeled tractor at oblique drawbar force. Soil Tillage Res 141, 32–43 (2014) 2. Nosian, J., Kuˇcera, M., Kosiba, J., Kuchar, P.: Construction of a hydraulic device to verify the operation of hydrostatic transducers. In: ICYS 2019. Nitra: Slovak University of Agriculture, pp. 143–150 (2019) 3. Tulík, J., Kosiba, J., Szabó, M., Varga, F., Kangalov, P.G., Mareˇcek, J.: Analysis of new biodegradable fluid during of the operating test. Agric. Forest Transp. Mach. Technol. 2(1), 11–15 (2015) 4. Tkáˇc, Z., Tulík, J., Jánošová, M., Štulajter, I.: Suitability of ecological hydraulic fluid application in tractor hydraulic circuit. Nauˇcni trudove 53(1), 175–178 (2014) 5. Majdan, R., Tkáˇc, Z., Abrahám, R., Kollárová, K., Vitázek, I., Halenár, M.: Filtration systems design for universal oils in agricultural tractors. Tribol. Ind. 39(4), 547–558 (2017) 6. Nosian, J., Halenár, M., Kuchar, P., Tulík, J., Furstenzeller, A., Kuˇcera, M.: Design of a device for verification of a hydraulic pump operation. Acta Facultatis Technicae. 24(1), 89–97 (2019) 7. Halenár, M., Nosian, J., Kuchar, P., Tulík, J., Furstenzeller, A.: Evaluation of hydraulic fluid during of the operating test. Acta Facultatis Technicae. 23(2), 73–80 (2018) 8. Kosiba, J., Tóth, F., Tulík, J.: The Laboratory research of biodegradable oils used in agriculture. Slovak University of Agriculture, ISBN 978-80-552-1890-8. 152 p (2018) 9. Tulík, J., Halenár, M., Kuchar, P., Jánošová, M.: Comparison of conventional hydraulic fluid with biodegradable fluid on the basis of laboratory test of durability. Traktori i pogonske mašine 21(1), 64–70 (2016) 10. Halenár, M., Kuchar, P.: Research of biodegradable fluid during operating test. In: MendelNet 2017. Brno, Czech Republic, 8–9 November. Brno: Mendel University in Brno, pp. 784–788 (2017) 11. Kosiba, J., Tkáˇc, Z., Majdan, R., Chrastina, J.: Pressure regimes of tractor hydraulic circuit. In: XXXVIII. mezinárodní konference kateder dopravních, manipulaˇcních, stavebních a zemˇedˇelských stroj˚u. Plzeˇn: University of West Bohemia, pp. 71–74 (2012) 12. Bafrnec, Š., Kosiba, J.: Degeneration processes of oil waste in the hydraulic circuit. In: Najnovšie trendy v poˇlnohospodárstve, v strojárstve a v odpadovomhospodárstve. Nitra: Slovenskápoˇlnohospodárskauniverzita, pp. 1–7 (2018) 13. Tóth, F., Rusnák, J., Nógli, D.: The influence of selected ecological oils on defined tribological system. In: XVIII. medzinárodná vedecká konferencia mladých 2016. Nitra: Slovenská poˇlnohospodárska univerzita. pp. 124–130 (2016) 14. Majdan, R., Tkáˇc, Z., Abrahám, R., Stanˇcík, B., Kureková, M., Paulenka, R.: Effect of ecological oils on the quality of materials of hydraulic pump components. In: Materials, Technologies and Quality Assurance, pp. 1–6 (2013) 15. Majdan, R., Kurekova, M., Nosian, J., Paulenka, R.: Zneˇcistenie univerzálnych olejov v traktoroch a návrh druhého stupˇna filtrácie. In: Spravodaj ATD SR 2, roˇc. 15, n. 2, s. 22–28 (2018) 16. Puškár, M., Jahnátek, A., Kuric, I., Kadárová, J., Kopas, M., Šoltésová, M.: Complex analysis of influence of biodiesel and its mixture on regulated and unregulated emissions of motor vehicles with the aim to protect air quality and environment. Air Qual. Atmos. Health 12, 855–864 (2019) 17. Tessmann, K.R.: Qualification of Qualification of Hydraulic Fluid through Pump Testing. Technology Transfer Publication.- Stilwater, Oklahoma, An FES/BarDyne (1998) 18. Zastempowski, M.: Test stands with energy recovery system for machines and hydraulic transmission. In: Journal of Research and Application in Agricultural in Agricultural Engineering, pp. 188–191 (2013)
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19. Košinár, M., Kuric, I.: Monitoring possibilitiesof CNC machintoolsaccuracy. In: 1st International Conference on Quality and Innovation in Engineering and Management (QIEM) (2011) 20. Kuric, I., Zajaˇcko, I., Císar, M.: Analytical intelligence tools for multicriterial of CNC machines. Adv. Sci. Technol. Res. J. 10(32), 59–64 (2016) 21. Kuric, I.: New methods and trends in product development and planning. In: 1st International Conference on Quality and Innovation in Engineering and Management (QIEM), pp. 453–456 (2011)
Properties Evaluation of New Biodegradable Fluid During Accelerated Durability Test ˇ Juraj Tulík1(B) , Lubomír Hujo1 , Juraj Jablonický1 , Jozef Nosian1 , and Jerzy Kaszkowiak2 1 Faculty of Engineering, Department of Transport and Handling, Slovak University of
Agriculture, Tr. A. Hlinku 2, 949 76 Nitra, Slovak Republic [email protected] 2 Faculty of Mechanical Engineering, UTP University of Science and Technology in Bydgoszcz, Al. prof. S. Kaliskiego 7, 85-796 Bydgoszcz, Poland
Abstract. The article deals with the evaluation of new universal gear hydraulic biodegradable fluid MOL Farm UTTO Synt by the accelerated durability test under laboratory conditions. The operational properties of the fluid were evaluated based on its influence on the technical state of the hydrostatic pump UD 25 during the test, specifically the flow rate and flow efficiency. From the physic-chemical properties was evaluated the viscosity of the fluid, additive depletion and contamination. The viscosity, flow rate and efficiency did not exceed the manufacturer’s specifications, but the level of contamination was higher. Nevertheless, the liquid shows good performance for use, as well as FT-IR spectroscopy, where no change was observed due to temperature effects on liquids and additive degradation and depletion. Keywords: Biodegradable fluid · Flow · Pollution · Laboratory test · FT-IR
1 Introduction Environmental protection is an actual topic already for several years, and it becomes a preferred problem in the established trend of economic development [19]. Hydraulic equipment is widely used in powerful mechanisms of agricultural and forest machines as well as in many other areas [4, 15]. Currently, hydraulic systems of mobile machinery are using mainly mineral base oils, which are having good properties proven by many years of use [14]. Using a fluid that is biodegradable reduces the cost of clean-up as well as the potential for polluting the environment [1]. With the development of technology and the improvement of production processes, there is space for the development of new ecological fluids that can serve as a substitute for conventional manufactured liquids [8]. For environmental reasons, it is important to replace mineral fluids and vegetable fluids and synthetic oil-base fluid petroleum oil-base fluids [17, 18]. Obviously, the new ecological fluids have their specific properties and influence on the hydraulic circuit of the machine, therefore one of the ways to prevent the machine damage is to perform fluid test under laboratory conditions [7]. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 205–214, 2021. https://doi.org/10.1007/978-3-030-75275-0_24
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Specific features characterize the ecological oils and fluids in compare with the mineral oil-base lubricants. Therefore, the ecological fluids have to be tested before they be applied in a tractor. One of the most important things is the temperature of fluid. In the case of biodegradable fluid, the working temperature has a specific limit and they cannot be exceeded, because it causes the accelerated fluid degradation. The laboratory and operation test serve to determine the ecological oils performance. The advantage of laboratory tests is an accelerated course. The various types of test benches load the oil in laboratory conditions [20]. With an experimental set of pressure measurements with numerical simulation for engines in laboratory conditions, we reduce the time required to perform operational measurements [13]. For this reason, the precise engineering production of individual elements of the hydraulic circuit is important, where it is important to monitor the accuracy of CNC machine tools using new methods and trends in product development and planning, where multilateral diagnostics of CNC machines is equally important [6, 9]. Also, the purity of lubricants is essential for the flawless condition and reliability of the fluid systems and is also reflected in the economical aspect of operation [5]. The identification of operating fluids is usually simple in practice thanks to the original packaging and its marking (indications) if they are stored correctly. However, operating fluids are very often stored in containers that are usually unmarked or poorly stored, and their individual properties can be degraded [2]. The transmission of energy is performed by the hydrostatic pump via a hydraulic fluid. For this reason, the hydrostatic pump was one of the main elements whose technical state largely contributes to the overall reliability of the hydraulic circuit, therefore, the fluid properties can by monitored via the state of hydrostatic pump [3]. The basic prerequisite for the correct function and effective care of hydraulic fluids is a suitably chosen methodology for testing fluids with monitoring the level of contamination of the working fluid. A comprehensive analysis of the effect of biological fluids and mixtures thereof has already been performed by author [11].
2 Material and Methods 2.1 Biodegradable Fluid MOL Farm UTTO Synt. The biodegradable fluid, which was used, is a new ecological fluid, which is made with synthetic base fluid based on poly-alpha-olefins. This fluid has high chemical stability and miscibility with mineral fluids. Ecological fluid MOL Farm UTTO Synt. is produced by MOL Group, Hungary. The main specifications of fluid are in Table 1. 2.2 Hydrostatic Pump UD 25 Tested synthetic oil-base fluid was applied into the laboratory stand which is used to load the hydrostatic pump UD 25 type. Hydrostatic pump belongs to the one-way hydrostatic pumps, which is used in the latest tractors Zetor Forterra for common fluid gear-hydraulic fill.
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Table 1. Specification of biodegradable fluid MOL Farm UTTO Synth Parameter
Unit
Value
Kinematic viscosity at 100 °C mm2 .s−1 10.22 Kinematic viscosity at 40 °C mm2 .s−1 58.14 Viscosity index VI
-
165
Pour point
°C
−42
2.3 Principle of the Fluid Laboratory Test Principle of operation of test device rests in loading of hydrostatic pump through cyclic pressure load with using electro-hydraulically valve, which is connected to output of hydrostatic pump. The change of the hydraulic valve position will change the direction of fluid flow which then flows through the pressure relief valve in the tank or directly into the tank fluid. These direction changes of flow result in pressure changes to hydrostatic pump output. The hydrostatic pump is loaded with cyclic pressure load for the duration of 106 cycles, at rated parameters. The test device was designed at the Department of Transport and handling, Faculty of Engineering, University of Agriculture in Nitra [11]. Author Majdan [10], evaluated the fluid properties under laboratory conditions based on wear of sliding pair of pins and bearing. The test was evaluated based on geometric dimensions and shape of pin and bearing. In our case, the laboratory test was realized based on technical state of hydrostatic pump. The tests were carried out based on following procedure: – Hydrostatic pump during the test will be loaded by laboratory stand for accelerated test of hydrostatic pump durability with cyclic pressure load changing from 0.1 MPa to the nominal pressure of hydrostatic pump 20 MPa. – The temperature of fluid will be kept on the defined value, that eliminating the possibilities of measurement errors caused by the difference of viscosity during test. – The quality of tested fluid will be evaluated based on flow efficiency of hydrostatic pump. – Flow efficiency will be calculated based on measured and statistical processing of fluid flow values, which are recorded by digital recording unit Q = f(p)n. – The test will take 106 load of pressure cycles. 2.4 Flow Characteristics The flow characteristics express the dependence of the fluid flow and the pressure,Q = f (p) n. Using the obtained characteristics, the properties of the ecological fluid can be evaluated based on the evaluation of the technical state of the hydrostatic pump. Wear of the hydrostatic pump results in a decrease in its leakage resistance, which is maximum for the new hydrostatic pump and during operation it decreases, which can be identified by the flow characteristics.
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During the laboratory fluid test, flow values are recorded in specified intervals (250,000 cycles) at rated parameters (pressure – 20 MPa, operating speed – 1,500 min−1 ), using a digital recording unit HMG 2020 developed by Hydac Company and sensor EVS 3100 (pressure sensor, flow sensor and temperature sensor in one). The curves of flow characteristics of the used hydrostatic pump were created from measured results. After that, flow values will be statistically processed by standardized normal distribution and we calculated the flow efficiency. The limit value that cannot be exceed is 20% of decrease of flow efficiency. This limit value is given by the manufacturer of the fluid. Then, the flow efficiency is expressed by the equation: ηpr =
Q VG . n
.100
(1)
where: • Q – flow of hydrostatic pump (dm3 .rpm) • VG – geometrical volume of hydrostatic pump (dm3 ) • n – nominal rotation speed of hydrostatic pump (rpm) 2.5 FT-IR Spectroscopy FT-IR stands for Fourier Transform Infrared, the preferred method of infrared spectroscopy. In infrared spectroscopy, IR radiation is passed through a sample. Some of the infrared radiation is absorbed by the sample and some of it is passed through (transmitted). The resulting spectrum represents the molecular absorption and transmission, creating a molecular fingerprint of the sample. Like a fingerprint no two unique molecular structures produce the same infrared spectrum. This makes infrared spectroscopy useful for several types of analysis [16]. The FT-IR spectroscopy was made by the FTIR spectrometer AVATAR 330, which will be used to evaluate the tested biodegradable fluid. 2.6 Solid Parts Filtration Solid parts filtration was performed with the FAS M2 measurement kit from Hydac, Slovakia. The principle of the solid impurity filtration method consists in filtering the test hydraulic fluid, diluted with perchloroethylene, by means of an electrical pump through the filter unit. The filter unit includes a membrane filter disk, on which particles of dirt are trapped. The filter discs thus obtained will be subjected to microscopic analysis using a Kappa 6000 microscope. The level of pollution can be determined by the comparative method.
3 Results and Discussions The flow values obtained by the HMG 2020 digital recording unit had to be converted to flow values at the specified speed according to the formula (1). The flow rates were
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processing for better viewing only for the new hydrostatic pump (0 cycles) and after the test (106 cycles). To better illustrate the course and magnitude of the change in the technical condition of the hydrostatic pump, the technical condition will be expressed in terms of flow. In the graph, we compared the flow characteristics of the new hydrostatic pump before and after the test. The flow characteristics indicate that the hydrostatic pump after the test showed operational wear due to the loss of flow (Fig. 1).
Fig. 1. The flow characteristics of hydrostatic pump UD 25 with biodegradable fluid MOL Farm UTTO Synt.
Fig. 2. The flow efficiencies of hydrostatic pump UD 25 with biodegradable fluid MOL Farm UTTO Synt.
Figure 2 shows the flow efficiency measured every 250,000 cycles, which show that the hydrostatic pump, during the test up to 750,000 cycles, showed an improvement in operating parameters, i.e. higher flow efficiency measured at a nominal pressure of 20 MPa compared to flow efficiency at the beginning of the test, a new hydrostatic pump. Upon completion of the test (1,000,000 cycles), a decrease of the flow efficiency of the hydrostatic pump was already noted. The flow efficiency at the beginning the test was 92.51% and it was calculated by formula (1), substituting the values of the geometric volume VG = 0.025 dm3 , the
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nominal speed n = 1500 rpm and the mean flow rate. The individual decreases in flow efficiency were calculated based on the technical condition of the UD 25. The test lasted until 106 pressure cycles, and up to 750,000 cycles were the values of flow efficiency bigger than the value of new hydrostatic pump. At the 750,000 pressure cycles were the flow efficiency the biggest (92.83%) than at the start of the test of 92.51%. The hydrostatic pump showed better operational properties than at the beginning, it was a running-in process. At the end of the test, the flow efficiency 91.55% was found, thus operational wear process occurred. The decrease of flow efficiency was only 1.04%, the value did not exceed the manufactures 20%. The kinematic viscosity at 40 °C and 100 °C was evaluated based on the values obtained every 250,000 cycles during the laboratory test.
Fig. 3. Kinematic viscosity at 40 °C and 100 °C of biodegradable fluid MOL Farm UTTO Synt.
Based on the viscosity results obtained at 40 °C and 100 °C (Fig. 3), only a slight decrease in viscosity values up to 750,000 cycles can be observed. After completion of the test, the viscosity value of the fluid increased slightly. The viscosity index values of the ecological fluid are in the “high viscosity index” category (above 110), i.e. the fluid is a viscosity-stable fluid. This is also confirmed by the results obtained from the measured viscosity values during the laboratory test, as the limit value has not been exceeded. The limit value is set by the manufacturer and is defined as ± 10% of the viscosity of the new fluid (at the beginning of the test). The IR spectra of new biodegradable fluid before the start and after the end of laboratory test. The evaluation of IR spectra is based on changes (increase/decrease of peaks) monitored during the courses of individual spectra [12]. In the area of 3,540 cm−1 , there is evaluated the oxidation of fluid on the basis of overheating. Temperature in the laboratory device was kept at the specified value, which was determined by operational measurements on the tractor. In terms of oxidation due to temperature, the fluid shows good properties and is suitable for the given tractor. In the area of 3,625 cm−1 , the water is present in the fluid. No change was recorded in this area (Fig. 4). Detergents are characteristic in the area of 1,630 cm−1 (Fig. 5). Since there was no change of peak in this area, depletion of additive did not occur during the test and the fluid maintained good quality properties. Solid parts filtration was made with FAS M2 kit, Kappa 6000 microscope and Moticam 1000 camera, were taken images of the contamination of the fluid after 250,000
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Fig. 4. Evaluation of thermal oxidation and water content
Fig. 5. Evaluation of impact of acid products and areas of detergents
cycles and at the end of the test, (1,000,000 cycles). The reference images contain contamination levels based on the size of particles and their classification to the three size groups, 4 µm, 6 µm and 14 µm. From the results obtained (Fig. 6 and 7) of the pollution analysis by filtering solid parts of the fluid, the level of contamination was determined and verified by comparing the images with the catalogue reference images (Fig. 6). Because the fluid can reach the highest level of contamination (contamination during the manufacturing process, improper storage) before starting the test, contamination was evaluated at 250,000 cycles when the fluid was filtered by the filter of laboratory stand. The image of solid parts filtration of 250,000 cycles, the closest match was with 21/19/16 pollution levels. The images show tiny wear particles that are characteristic of the running-in process. The largest wear particle which was found did not exceed 10 µm. When comparing the contamination images obtained after the test (1,000,000 cycles) with the reference images, the smallest difference was found in the reference image with the contamination level of 22/20/17 (Fig. 7). When comparing the images to the reference images, it was
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Fig. 6. The samples of filtration of solid parts after 250,000 cycles and the reference image of 21/19/16 level pollution
Fig. 7. The samples of filtration of solid parts after 1,000,000 cycles and the reference image of 22/20/17 level pollution
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seen that there were fewer wear particles larger than 6 µm and 14 µm on the obtained image, confirming the accuracy of the measured results in the ISO 4406 measurement of pollution, when the level of pollution was determined 22/19/14.The reference image catalogue did not contain image with a pollution level of 22/19/14. The image shows small wear particles resulting from the completed running-in process as well as larger particles that may indicate the ongoing initial wear phase. The largest wear particle found in the images after the test was 21.5 µm long.
4 Conclusions The article deals with the evaluation of biodegradable fluid marked as MOL Farm UTTO Synt., which belongs to the group of universal transmission hydraulic fluids. The performance of the fluid has been evaluated based on its influence on the technical state of the selected UD 25 hydrostatic pump often used tractors. From the values of flows of the accelerated laboratory durability test, was the values statistically processed to the values of flow efficiency. The test lasted until 106 pressure cycles, and up to 750,000 cycles were the values of flow efficiency bigger than the value of new hydrostatic pump. At the 750,000 pressure cycles were the flow efficiency the biggest, 92.83% found at the start of the test of 92.51%. The hydrostatic pump showed better operational properties than at the beginning (92.51%), it was a running-in process. At the end of the test, the flow efficiency 91.55% was found, thus operational wear process occurred. The influence of the fluid on the technical state of the hydrostatic pump shows very good properties. In terms of viscosity, the fluid has not exceeded the manufacturer’s stated limit values and exhibits good properties. No degradation of the liquid due to overheating or the presence of acidic components was found in FT-IR analyses. In the pollution evaluation, the particulate filtration samples were analysed by comparative method, and at the end of the test a higher level of contamination was found (22/20/17), which could be removed by additional filtration. From the fluid achieves good results and is suitable for further testing under operating conditions. Acknowledgments. This work was supported by project VEGA 1/0155/18 “Applied research of the use of ecological energy carriers in agricultural, forestry and transport technology.” This work was supported by project KEGA 028SPU-4/2019 “Practical utilization of design and testing knowledge of transmission systems of hydraulic mechanisms of mobile agricultural and forestry machinery.” This work was supported by project Bilateral Cooperation SK-PL-18–0041 “The Development of Scientific Cooperation in the Study of the Effects of Biofuels in Road Transport, Including Environmental Impact.” This publication was supported by the Operational Program Integrated Infrastructure within the project: Demand-driven research for the sustainable and innovative food, Drive4SIFood 313011V336, cofinanced by the European Regional Development Fund.
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Plasticity Studies During Deformation Under Conditions of Significant Negative Values of the Stiffness Coefficient of the Stress State Ihor Shepelenko1(B) , Yuri Tsekhanov2 , Yakiv Nemyrovskyi1 , Pavlo Eremin1 , and Oleh Bevz1 1 Central Ukrainian National Technical University, 7 Universytetskyi Avenue,
Kropyvnytskyi 25006, Ukraine 2 Voronezh State Technical University, 84 20 let Oktyabrya Street, Voronezh 394026, Russia
Abstract. The study of the stress-deformed state of cylindrical cast iron samples under conditions of their volumetric compression was carried out applying the finite element method using the Deform software package. A technique has been developed for modeling the settlement of studied samples, which makes it possible to calculate the stress-deformed state, which is necessary to construct a plasticity diagram for low-plastic materials with significant negative values of stiffness coefficient of the stress state. Analysis of the stress-deformed state showed a significant unevenness of its distribution over the volume of settlement sample, and, consequently, a significant difference between the settlement scheme with limited radial displacements along the outer surface of the sample from the known free settlement scheme of a cylindrical sample. It has been established that the stiffness coefficient of the stress state changes significantly over the wall thickness, which allows the process of SCH20 cast iron deformation at different values of the stiffness coefficient and use the obtained results to construct its plasticity diagram. The results obtained by modeling using the finite element method and calculated analytical model showed their good overlapping, both in the value of the accumulated deformation and in the value of the stiffness coefficient of the stress state. Keywords: Plasticity · Stress-deformed state · Compression · Finite element method · Cast iron · Stiffness coefficient of the stress state
1 Introduction One of the important characteristics of the processed part quality and its performance, especially under the conditions of cyclic operational loads, along with the roughness, state and depth of the surface layer hardening, and its residual stresses, is the plasticity parameter [1]. Among the processes of cast iron SCH20 parts plastic forming, deforming broaching is of particular interest. The plasticity study of cast iron products during their deforming broaching is an urgent problem for a number of reasons. First, it is necessary to determine © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 215–223, 2021. https://doi.org/10.1007/978-3-030-75275-0_25
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the ultimate deformation of such materials depending on the type of stress state. This will make it possible to correctly select such a technological parameter as the allowable value of residual plasticity, which, according to [2], has a very significant effect on the performance of finished products, especially those operating under cyclic loads. In addition, according to the authors of [3], the value of plasticity resource used in operations preceding chemical-thermal treatment (carburizing, nitriding) has a significant impact on minimizing the time of these operations, as well as on obtaining an improved structure after heat treatment. The metal plasticity, which is determined by the accumulated plastic deformations by the time of destruction, depends on a number of factors, among which, in addition to the nature of the material itself, the most important are the type of stress state, temperature, rate and deformation history [4]. The dependence of plasticity on the type of stress state is characterized by the plasticity diagram, which is a mechanical characteristic of the material. The plasticity diagram is represented in the coordinates: “stiffness coefficient (type) of the stress state η – accumulated deformation eult ” and is the same for various stress states [4, 5]. As shown in [6], during deforming broaching, the workpiece material in the contact zone is under conditions of strong volumetric compression. This is especially favorable when processing products from low-plastic materials. The construction of the plasticity diagram is especially important in the processing of low-plastic materials by plastic deformation, for example, graphite-containing cast iron SCH20, the possibilities of its plastic deformation are limited by destruction. To obtain the data necessary for constructing the plasticity diagram, it is necessary to conduct a study of the material mechanical properties at a large negative hydrostatic pressure. Thus, the plasticity studies of low-plastic cast iron SCH20 during its forming by deforming broaching become relevant.
2 Literature Review The scientific basis for plastic processing of low-plastic materials is formulated in [7], where it is indicated that when certain conditions are created (close to all-round compression), even brittle materials can behave like plastic, that is, have certain residual deformations. Conditions close to all-round compression can be created during deforming broaching in the contact zone of the tool with the workpiece [8]. This allows us to make an assumption about the possibility of products plastic processing from such a semi-brittle (low-plastic) material as cast iron by deforming broaching. Recommendations for the selection of deforming broaching modes and plasticity resource evaluation used in products processing from plastic materials are presented in a number of works [2, 3, 9]. However, it is quite obvious that this issue has not been sufficiently studied for low-plastic materials. In [10] it is indicated that the processing of low-plastic materials by deforming broaching must be performed at negative values of the coefficient of the stress state. In this case, plastic deformations of the workpiece should be avoided, that is, its outer surface should not deform plastically, because this will inevitably lead to its destruction.
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The plastic zone should only cover the inner part of the workpiece wall. In this case, due to the creation of hydrostatic pressure from the external un deformed layers, conditions are created for the successful processing of cast iron products. The authors of the works [2, 8] experimentally determined the ultimate deformations of cast iron bushings during deforming broaching. However, the presented practical recommendations on the choice of broaching modes and tool geometry do not allow to reveal the regularities of the deformation process, as well as hardening under the action of plastic deformation, and to evaluate the state of deformation at different stages of processing, as well as to determine the resource of the used and residual plasticity. There is an opinion [4] that there are no fundamental differences in the deformed state of workpieces when processing plastic and low-plastic materials by deforming broaching. This is confirmed by the data of [3, 11], where it is shown that the schemes of interaction of the tool with the workpiece for plastic and low-plastic materials practically do not differ from each other. In both cases, the deformation zone consists of a contact area and two non-contact zones adjacent to it. The difference is only observed in the values of the contact zone length and the non-contact zones sizes. In this case, the main accumulation of damage occurs in the non-contact zone in front of the contact area, where the compression stress state takes place under conditions of plane deformation. A decrease of this zone, in our opinion, leads to an increase of the processed material plasticity resource. Technological influence on the size of this zone can be carried out, for example, by changing the amount of tension on the element. Moreover, as indicated in [11], the less tension on the element, the smaller the non-contact zone, and the higher the plasticity. Consequently, for a given value of hole total deformation, deformation must be carried out with the minimum allowable tension on the element. The above data indicate the possibility of plastic deformation of cast iron products, but in order to quantify the ultimate deformations values, select the expansion deformation values, and determine the residual plasticity values, it is necessary to construct a plasticity diagram for cast iron. To construct a plasticity diagram, it is necessary to perform mechanical tests of the studied materials under simple loading and deformation conditions, when the stresses vary in proportion to one parameter. For plastic materials, the authors of [10] recommend the following tests: tensile, torsion, compression. For such a low-plastic material as cast iron, tensile tests, uniaxial and biaxial tensile showed a complete absence of plastic deformation, while brittle fracture of the samples took place [11]. At the same time, during compression tests, where coefficient of the stress state η = 0 and η = −1, respectively, insignificant plastic deformation of the samples was recorded. There are no data on the plasticity of cast iron under conditions of volumetric compression in the available literature. Consequently, there is a need to study the patterns of cast iron samples plasticity change during compression at significant negative values of the stiffness coefficient of the stress state. To do this, first, it is necessary to study the stress-deformed state (SDS) of the sample under conditions of volumetric compression and construct a plasticity diagram including a section with significant negative values of the stiffness coefficient of the stress state. The availability of such information will make it possible to develop
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technological methods for controlling the plasticity resource of low-plastic materials during deforming broaching. The aim of the presented work is: – study of SDS under conditions of workpieces volumetric compression from cast iron SCH20; – plastic properties study of low-plastic materials with significant negative values of the stiffness coefficient of the stress state.
3 Research Methodology Given the lack of studies of low-plastic materials SDS, there is a need to develop a methodology for modeling cast iron samples during compression. The study of cast iron samples SDS was carried out by modeling their settlement under conditions of constrained circumferential deformation on their outer surface using the finite element method (FEM) according to the scheme shown in Fig. 1, using the Deform software package. Data preparation for modeling was carried out in several stages. Initially, the object of research was set: sample 1 from cast iron SCH20 with the following dimensions: outer diameter d out = 8 mm; inner diameter d in = 2 mm; height H = 8 mm. Steel 40HG was used as the material for punch 2 and matrix 3. The diameters of punch 2 and matrix 3 were set to 8–0,1 mm and 30–0,1 mm, respectively. Modeling conditions: punch moving speed V = 0.1 mm / s. The problem statement is axisymmetric. The next step is to determine the properties of materials. The Deform-3D software package has its own library with properties files of metals and alloys. However, to improve the accuracy of calculating the data for the test sample material, the experimentally obtained compression curve of SCH20 cast iron was used (Fig. 2). Thus, the properties of the studied material were set by the compression curve (Fig. 2), hardness HB = 1.7 GPa, Poisson’s ratio μ = 0.27 and Young’s modulus E = 1.6 × 105 MPa. When modeling the sample settlement process using the Deform software package, the same conditions were used as in the experiments. So the studied sample 1 (Fig. 1) in the form of a sleeve with an inner round hole is freely installed in the hole of the matrix 3, which is rigidly fixed on the hydraulic press table. At the beginning of the research, the punch 2 is located at a small distance above the upper end of the sample 1, and its geometric dimensions provide a minimum gap between it and the walls of the matrix hole. The working movement of the punch 2 is set by its monotonic longitudinal movement at a distance of 4 mm through the hole of the matrix 3, which in turn rests on a fixed base. Processing is carried out with one punch. To the top of the test sample 1, installed in the hole of the matrix 3, an axial load was applied by the punch 2, sufficient for plastic deformation of the research object, followed by unloading. The maximum state of settlement corresponded to the complete closure of the sample inner hole. Its initial inner radius was r 1 = 2 mm, and the outer radius was r 2 = 8 mm, which corresponded to the dimensions of a part with an infinite wall thickness [5]. The height of the deformed sample is H = 8 mm.
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Fig. 1. Scheme of cold deposition treatment: 1 – test sample; 2 – punch; 3 – matrix
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Fig. 2. Experimentally obtained compression curve for cast iron SCH20
The settlement was modeled step by step. The entire settlement range was split into 40 steps. When at the last step the compressive force and the value of the stress intensity began to increase sharply, the simulation process was stopped. At the same time, the change in the geometric dimensions of the studied sample and the SDS parameters were investigated.
4 Results The results of modeling in the form of isolines and parameters history curves for individual material points (pointtracking) using the proposed method are presented below. Figure 3 shows the results of SDS calculations for the 10th step of settlement, when the average axial deformation of the compressed sample is 0.1 (10%). Figure 3, a – shows the distribution of the deformation intensity e0 . As you can see, at the outer surface of the sample, which is in contact with the rigid matrix, it is small and increases towards the inner surface. Figure 3, b – shows the distribution of stress intensity σ 0 , which, following the patterns of change e0 , also increases towards the center of the sample. The radial stress σ r (Fig. 3, c) is negative and increases in modulus towards the outer surface. On the inner free surface, it differs slightly from zero, which is associated with inevitable errors in the numerical modeling by the FEM. Axial stress σ z (Fig. 3, d) is compressive and increases towards the outer surface, which indicates an uneven distribution of contact pressures between the sample and the punch.
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The circumferential stresses σ ϕ (Fig. 3, e) are compressive and also increase towards the periphery. Figure 3, f shows the distribution of the deformation rate intensity ξ0 , which is also significantly nonuniform and increases toward the inner free surface. The performed analysis of SDS shows a significant unevenness of its distribution over the volume of the settlement sample, i.e. a significant difference between the settlement scheme with limited radial displacements along the outer surface of the sample from
Fig. 3. Field of accumulated deformation distribution e0 (a), stress intensity σ 0 (b), radial stress σ r (c), axial stress σ z (d), circumferential stress σ ϕ (e), intensity of deformation rates ξ0 (f) of the sample at the last step and graphs its changes throughout the deformation history
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Fig. 4. Distribution of hydrostatic pressure σ over the thickness of the sample wall (a) and the stiffness coefficient of the stress state η (b) of the sample at various states of its settlement k: 1 – k = 0.05; 2 – k = 0.1; 3 – k = 0.3; 4 – k = 0.4
Fig. 5. Change in the stiffness coefficient of the stress state η depending on the state of sample settlement k for different points
the known free settlement scheme of a cylindrical sample. The latter must be taken into account when experimentally determining the plasticity of materials. Figure 4, a, b shows the distribution over the wall thickness of the hydrostatic pressure σ and the stiffness coefficient η for various states of settlement k = 0.05 ÷ 0.4. It shows that the value η changes significantly along the wall thickness, which allows the deformation process of SCH20 cast iron at different values of the stiffness coefficient η and use the obtained results to construct its plasticity diagram. As can be seen, in the working range of the state of settlement k = 0.1 ÷ 0.4, the value of η near the inner and outer surfaces of the sample practically does not change, and in the middle of the thickness this change is about 12%, which makes it possible to maintain practically constancy of value η in the experimental implementation of this settlement scheme. This is important for construction the plasticity diagram. A significant deviation from this condition for a low state of settlement with k = 0.05 (5%)
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is practically insignificant, since the ultimate deformation of cast iron in compression is 0.12 (12%). The marked patterns of η change are more clearly seen in Fig. 5. Comparison of sample settlement modeling results, obtained using FEM and calculated analytical model [12], shows their good overlapping, both in value of the accumulated deformation and the value of the stiffness coefficient of the stress state.
5 Conclusion The presented material allowed us to make the following conclusions: – a method has been developed for modeling the settlement of a cylindrical cast-iron sample under conditions of volumetric compression using FEM in the Deform software package, which makes it possible to calculate the SDS of a sample during compression, which is necessary to construct a plasticity diagram for low-plastic materials with significant negative values of the stiffness coefficient of the stress state; – modeling the settlement process of a cast iron sample using FEM showed good overlapping with the previously obtained theoretical data; – this technique can be recommended for the plasticity experimental study of brittle and low-plastic materials and for construction of their plasticity diagram under conditions of strong volumetric compression.
References 1. Suslov, A.G.: The Quality of Machine Parts Surface Layer. p. 320. Moscow (2000) (in Russian) 2. Rosenberg, A.M.: Mechanics of Plastic Deformation in the Processes of Cutting and Deforming Broaching. p. 320. Kiev (1990) (in Russian) 3. Rosenberg, O.A.: Technological Mechanics of Deforming Broaching. p. 203. Voronezh (2001) (in Russian) 4. Del, G.D.: Technological Mechanics. p. 174. Moscow (1978) (in Russian) 5. Grushko, A.V.: Maps of Materials in Cold Working by Pressure. p. 348. Vinnitsa (2015) (in Russian) 6. Nemyrovskyi, Y., Shepelenko, I., Posviatenko, E., Tsekhanov, Y., Polotnyak, S., Sardak, S., Bandura, V., Paladiichuk, Y.: Designing the structures of discrete solid-alloy elements for broaching the holes of significant diameter based on the assessment of their strength. Designing the structures of discrete solid-alloy elements for broaching the holes of significant diameter based on the assessment of their strength 7(105), 57–65 (2020) https://journals.uran. ua/eejet/article/view/203524 7. Bridgman, P.V.: The Latest Work in the Field of High Pressures. p. 300. Moscow (1948) (in Russian) 8. Chernyavsky, O.V., Sivak, I.O., Lopatenko, S.G.: Determining the limit of process application of deforming broaching in the processing of cast iron. In: Improving the Technical Level of Agricultural Production and Engineering, pp. 82–85 (2016) (in Ukrainian) 9. Nemyrovskyi, Y.B., Krivosheya, V.V., Sardak, S.E., Shepelenko, I.V., Tsekhanov, Y.A.: The use of deforming broaching for enhancing the efficiency of cutter chisels. Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu 2, 61–66 (2020) https://doi.org/10.33271/nvngu/ 2020-2/061
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10. Tsekhanov, Y.A., Sheikin, S.E.: Mechanics of Workpieces Forming During Deforming Broaching. p. 200 Voronezh (2001) (in Russian) 11. Nemirovskyy, Y., Chernyavskyy, O., Eryomin, P., Tsekhanov, Y.: Issues about limit plastic deformations of deforming broaching of cast iron parts. Sci. J. Ternopil Natl. Tech. Univ. 1(81), 88–97 (2016) 12. Shepelenko, I.V., Tsekhanov, Y.O., Nemyrovskyi, Y.B., Yeromin, P.M., Mirzak, V.Y.: On the question of the parts processing quality evaluating by cold plastic deformation in coefficients of plasticity. In: Proceedings of the VI International Scientific and Practical Conference "Modern Technologies of the Industrial Complex - 2020, vol. 6, pp. 163–166 (2020) (in Ukrainian)
Parameters of Pipe Narrowing by Radial Forging with Inner Thread Tightening Himzo Ðuki´c1 and Mirna Noži´c2(B) 1 University of Mostar FSRE, Mostar, Bosnia and Herzegovina 2 Faculty of Mechanical Engineering, University “DžemalBijedi´c”
of Mostar, Mostar, Bosnia and Herzegovina [email protected]
Abstract. The paper presents experimental results of pipe narrowing by radial forging, with simultaneous tightening of the internal thread. The workpieces are intended for the most responsible elements in aviation. The paper gives expressions for the calculation of: number of passes, dimensions by phases, dimensions of mandrels, expected values of thickening, inner diameter of the pipe and optimal values of the degree of deformation. Keywords: Pipe narrowing · Radial forging · Narrowing parameters · Internal thread twisting · Fiber twisting
1 Introduction Narrowing of pipes can be done in several ways, the most famous of which are: radial forging, rotary forging, cold pressing in tools and pressing in tools in the hot state [1, 10]. Simultaneous narrowing of the pipe and tightening of the internal thread can only be performed by radial forging. Tightening of the internal thread is mandatory when making the load-bearing elements, which are located in the command chain of the aircraft. The tapered sections of pipe have a cylinder-cone-cylinder shape. Narrowing and tightening of the internal thread can be performed on special machines, which enable: radial forging, rotary movement of the pipe, horizontal movement of the pipe and placement of the mandrel for thread threading. Figure 1 shows the basic movements of the machine and the dimensions of the workpiece. The markings in the figure represent: v2 the speed of oscillation of the striker, v1 - the speed of movement of the pipe, n1 - the number of revolutions of the pipe, d0 -initial diameter of the pipe, d1 -final diameter of the narrowed pipe and α-angle of the cone. In order to achieve all these movements, it was necessary to construct and make a special machine, which enables: variable number of pipe revolutions, variable speed of pipe approach, variable number of blows, change of strikers of different geometry, placement of threaded mandrel in the last operation and automatic limiting pipe displacement [8].
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 224–230, 2021. https://doi.org/10.1007/978-3-030-75275-0_26
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Fig. 1. Basic movements of tools and workpiece
2 Experimental Research Pipes with diameters: 16, 18 and 20 mm thick were used for experimental research. s0 = 1 mm, made of material AU4G1T4. The appearance of the narrowed part of the pipe is shown in Fig. 2.
Fig. 2. Appearance of the narrowed part of the pipe and the internal thread
The designations in Fig. 2 are: d0 -initial pipe diameter, s0 -initial pipe thickness, d1 final narrowed pipe diameter, s1 -final wall thickness of the narrowed part of the pipe, α-angle of the cone of the narrowed part, lk -length of the conical part of the pipe, lc - the length of the cylindrical part of the pipe on which the thread is threaded. When narrowing the pipe, there is: a decrease in the diameter of the pipe, an increase in the thickness of the wall, an increase in the initial length of the pipe and the twisting of the outer fibers on the narrowed part of the pipe. These dimensional changes can be expressed through the following deformations: – Narrowing ratio: md1 =
d1 d2 di ; md2 = ; mdi = d0 d0 d0
(1)
ms1 =
s1 s2 si ; ms2 = ; msi = s0 s0 s0
(2)
– Thickening ratios:
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– Logarithmic deformation of cross section: ϕu = ln
A0 A1
(3)
In order to monitor the twisting of the outer fibers, circular nets were applied electrochemically to the pipe, Fig. 3.
Fig. 3. Display of mesh and twisted outer fibers
The twisting of the outer fibers of the pipe is caused by the action of a friction force, which has the direction of the tangent directed opposite to the direction of rotation of the pipe. By narrowing the tube, the initial shape of the circle is deformed into an ellipse. By measuring the longitudinal and transverse axes of the ellipse, logarithmic deformations in each part of the pipe narrowing can be calculated [9]: ϕi = ln
Di D0
(4)
where: D0 -diameter of the circle of the applied grid, Di -length of the axis of the ellipse.
3 Results of Experimental Research Based on a large number of performed experiments, the optimal values of the narrowing ratio were established. – For the first narrowing, ie the first passage: md1 = 0, 76 ÷ 0, 8 – For the second narrowing, ie the second passage: md2 = 0, 88 ÷ 0, 90 – For the last taper in which the thread is tightened: mdn = 0, 93 ÷ 0, 95
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If the mean narrowing ratio is adopted md = 0, 84 for all passes and md = 0, 95 for thread twisting, the expression for the calculation of the required number of passes is obtained in the form [6]: n = 0, 705 + 13, 2 log
d0 dn
(5)
where: d0 -initial diameter of the pipe, dn -minimum diameter to which the pipe is forged. The count number of passes should be rounded to an integer. The mathematical model for determining the thickening functions depending on the narrowing ratio, obtained by regression analysis, has the form: −0,822 di (6) si = 1, 04 · s0 · d0 where: s0 -initial pipe wall thickness, di-pipe diameter after narrowing and d0 -initial pipe diameter. Due to the elastic straightening of the material, there is always a difference between the occupied diameter and the actually obtained diameter of the pipe after narrowing. Based on a large number of measurements, the expression for calculating the diameter of the mandrel was obtained in the form: 1,44 di (7) dt = di − 1, 281 d0 where are: the di-diameter of the pipe to be obtained by narrowing and the d0-initial diameter of the pipe. In the process of narrowing, the initial length of the pipe increases. The final length of the pipe is calculated by the expression: −3,68 di (8) L = L0 + 0, 633 d0 where: L0 - initial pipe length, di -pipe diameter after narrowing, d0 -initial pipe diameter. Based on the experimental results of narrowing of pipes with diameters: 16, 18 and 20 mm, wall thickness s0 = 1 mm from AU4G1 in the soft annealed state, a diagram of the dependence of the total narrowing ratio and the total thickening ratio was obtained, Fig. 4. The experimental results are represented by a black curve, and the mathematical approximation by a dashed red curve. The mathematical form of the experimental results can be described by a third-order polynomial in the form: mdu = 2, 5 · m3su − 9, 7 · m2su + 11, 9 · msu − 3, 7
(9)
The relationship between the total narrowing ratio and the total thickening ratio given by expression (9) completely agrees with the obtained experimental results. In the case of aeronautical elements, one of the important parameters that needs to be controlled is the twisting of the outer fibers, which occurs during radial forging and threading [2].
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Fig. 4. Diagram of the dependence of the total narrowing ratio and the total thickening ratio
Fig. 5. Diagram of the dependence of the torsion angle on the performed logarithmic degree of deformation
Using expression (4) for logarithmic deformations of ellipses caused by deformation of electronically applied circles, Fig. 3 and measuring the torsion angle of the axes of circles and ellipses along the tube, a diagram of the dependence of torsion angle on the performed logarithmic degree of deformation was obtained, Fig. 5. From the diagram in Fig. 5 it can be seen that the twisting angle is higher on the cylindrical part of the pipe (curve B) due to the increased resistance created by the tightening of the internal thread. The formation of the internal thread is done using a special mandrel, which has a thread profile that you want to get. The outer diameter of the mandrel differs from the profile of the notch, which is used to incise the inner thread. This difference is conditioned by the way of filling the profile by forging, i.e. plastic deformation of the
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material. In the penultimate operation, the inner diameter of the tapered tube must match the outer diameter of the threaded mandrel. In the internal thread setting phase, the pipe displacement speed v1 and the speed n1 (Fig. 1) must be adjusted to the profile and thread pitch to be obtained.
4 Conclusion Conducted experimental investigations of pipe narrowing with simultaneous tightening of the internal thread were performed on a machine, which was designed and manufactured for this purpose. When narrowing and at the same time anchoring, the outer diameter decreases, the wall thickness increases and the length of the pipe increases. Technological parameters related to: material, heat treatment, percussion displacement, number of percussion strokes, pipe rotation speed and shape of the thread mandrel are determined on the basis of original experimental research, the results of which are given in the paper. The required number of narrowing passes is calculated by expression (5). The expected thickenings of the pipe are calculated by expression (6), and the elastic return at each passage is calculated by expression (7). The final length of the pipe is determined by expression (8). The relationship between the narrowing ratio and the thickening ratio is given by expression (9). The twisting of external fibers was determined on the basis of network deformations, previously applied electrochemically (Fig. 5). Based on the above expressions, for all important process parameters, it is possible to design the technology of pipe narrowing with simultaneous tightening of the internal thread.
References 1. Noži´c, M., Ðuki´c, H.: The impact of the deformation redistribution on the special narrowing force. In: 5th International Conference New Technologies, Development and Application NT-2019, Sarajevo, Bosnia and Herzegovina (2019) 2. Roy, B.K., Korkolis, Y.P., Arai, Y., Araki, W., Iijima, T., Kouyama, J.: Experiments and simulation of shape and thickness evolutionin multi-pass tube spinning. In: Numisheet 2018, IOP Conference Series: Journal of Physics: Conference Series, vol. 1063 p. 012087 (2018) 3. Centeno, G., Silva, M., Alves, L., Vallellano, C., Martins, P.: Towards the characterization of fracture in thin-walled tube forming. Int. J. Mech. Sci. 119(2016), 12–22 (2016) 4. Ye, Y., Liu, Y., Althobaiti, A., Xie, Y.-X.: Localized bulging in an inflated bilayer tube of arbitrary thickness: effects of the stiffness ratio and constitutive model. Int. J. Solids Struct. 176–177(2019), 173–184 (2019) 5. Magrinho, J.P., Silva, M.B., Centeno, G., Moedas, F., Vallellano, C., Martins, P.A.F.: On the determination of forming limits in thin-walled tubes. Int. J. Mech. Sci. 155(2019), 381–391 (2019) 6. Noži´c, M., Ðuki´c, H.: Eksperimentalno odredivanje graniˇcnih stupnjeva deformacije u procesima proširivanja i sužavanja. In: International Conference MATRIB 2018, Vela Luka, Hrvatska (2018) 7. Li, C., Daxin, E., Zhang, J., Yi, N.: Investigation of the geometry of metal tube walls after necking in uniaxial tension. Metals 7(3), 100 (2017)
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8. Noži´c, M., Ðuki´c, H.: Utjecaj naˇcina projektiranja alata na silu specijalnog sužavanja. In: International Conference MATRIB 2017, Vela Luka, Hrvatska (2017) 9. Ðuki´c, H., Noži´c, M.: Limit values of maximal logaritmics strain in multi-stage cold forming operations. J. Technol. Plast. 40(1) (2015) 10. Ðuki´c, H., Noži´c, M.: Obrada deformisanjem, drugo izdanje, Univerzitet, Džemal Bijedi´c, Mašinski fakultet Mostar (2018) 11. Halyna, K.: Method of predicting necking true stress in a thin-walled tube under a complex stress state. Strojnícky cˇ asopis – J. Mech. Eng. 70(2), 101–116 (2020) 12. Dick, C., Korkolis, Y.: Mechanics and full-field deformation study of the ring hoop tension test. Int. J. Solids Struct. 51(2014), 3042–3057 (2014) 13. Kim, H.S., Kim, S.H., Ryu, W-S.: Finite element analysis of the onset of necking and the postneckingbehaviour during uniaxial tensile testing. Mater. Trans. 46(10), 2159–2163 (2005) 14. van den Boogaard, A.H., Huetink, H.: Prediction of sheet necking with shell finite element models. In: 6th International ESAFORM Conference on Material Forming - Salerno, Italy (2003)
Research of the Surface Roughness Parameters After End Milling Matej Kljajo1 and Danijel Šogorovi´c2(B) 1 Škutor d.o.o., Mostar, Bosnia and Herzegovina 2 University of Mostar, FSRE, 88000 Mostar, Bosnia and Herzegovina
[email protected]
Abstract. This paper examines the influence of technological parameters (elements of the cutting process) on the roughness of the surface in the end milling process. The aim of the paper is to analyse the impact of cutting speed (vc ) and feed speed (vf ) on the roughness parameter Ra . The machine tool, tool used, the material and the device for measuring of the roughness parameters are shown. This experiment gives an adequate mathematical model of the first degree of this influence for prototype of universal end mill (N type) for milling of materials of P group, which describes the effect of technological parameters on roughness. Keywords: End mill · Surface roughness · Technological parameters · Model
1 Introduction Milling is the material removal process which produces flat, curved and stepped surfaces, grooves, threads, gears and generally contours of regular or irregular bodies. By using the different types of milling cutters, it is possible to process different types of materials, from wooden materials to hard metal alloys, with very good quality of the machined surface, without any additional processing. With the development of high-speed CNC machining centres, the use of milling is increased as a primary process of processing raw materials and semi-finished products, but also as final processing of products [1]. End milling cutters (End mills) are a group of milling tools that have the possibility of combined (both face and peripheral) milling, and depending on the type and shape are used to make continuous flat and curved surfaces, grooves, channels etc., and the qualities of the machined surface range from IT9 to IT15 [2], depending on whether it is fine or normal milling or deep grooves are made. End mills are made from one piece by grinding on specialized CNC 5-axis machines, and are made out of high-speed steel (HSS) and, most often, hard metal, tungsten carbide, with or without coating. The DIN 1836 standard divides end mills (as well as all other cutting tools with helical blades) into three groups according to the purpose, for which types of materials they are used, so there are three groups for fine machining and four for hard machining.
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 231–238, 2021. https://doi.org/10.1007/978-3-030-75275-0_27
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For the fine machining, end mills are divided into three groups: • N (from german “normalen” - normal) - formaterials with normal hardness and strength values • H (from german “harten” - hard) - for hard ferrous materials and/or materials with short chip • W (from german “weichen” - soft) - for soft materials and/or materials with long chip According to the ISO standard, workpiecesused in machining with cutting are classified into 6 categories. The most common category “P” represents all alloys where iron has the largest proportion (except austenitic and stainless steels), which have a long chip in the machining with cutting. This is the most commonly used group of materials ˇ in the machining process, and includes non-alloy steels such as C1430 (C35 acc. to ˇ ˇ DIN), C1531 (Ck45), C3135 (28Mn6), low-alloy steels such as: 42CrMo4, St50, Ck60, 100Cr6 and high-alloy steels such as X40CrMo H13, M42, 12Ni19, etc. End mills for these materials are almost always made of carbides M1 and M2 group, generally they have a higher helix angle for fine milling (from 30° to 40°, which corresponds to the N group of hard metal cutters) and a larger number of cutting edges (usually 4 or 6) [3,4].
2 Experiment In this paper, the experiment has been performed and provides a mathematical model of the influence of the machining condition on the roughness of the machined surface for a prototype of a universal end mill which is used for machining of P group materials. The selected technological parameters are cutting speed (vc ) and feed speed (vf ), and the machining process will be observed and the quality of the machined surface will be measured during peripheral milling with prototype end mill. A prototype of a universal end mill with four cutting edges, has been used as a test tool. Tool has been developed at SME Škutor during student praxis. The surface roughness Ra was chosen as the output value, from which the function of machinability follows: Ra = f (vc , vf )
(1)
The factorial design of experiment 22 has been selected, which has 2 factors, on two levels in order to obtain a model of the relation of roughness on the above input values. A certain number of experiments (n = 4) at the central point of the plan is added to this design. Therefore, the total number of experiments is calculated according to the equation: N = 22 + 4 = 8
(2)
The values of the input factors, the cutting speed and the feed speed, are determined as shown in the Table 1. The matrix of the experimental plan is defined by using of the computer program Design - Expert v.12.
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Table 1. Levels of input factors in factorial design, “22 + 4” Factor
Xi(min) Xi(sr) Xi(max)
vc [m/min]
160
vf [mm/min] 600 Code
−1
230,5 301 900
1200
0
1
2.1 Other Machining Parameters Other machining parameters, such as depth and width of cut are taken as constant, where: • ap = l 2 = 26 mm- optimal mode of fine, peripheral milling, where the heat during machining is evenly distributed around the edge of the tool [5–7]. • ae = 0,1d 1 = 1,6 mm – fine machining conditions, where in the case of end milling cutter the value of the cutting depth is 1.6 mm [8]. It is important to emphasise that the process was performed with usage of a coolant device - emulsion, and great attention was paid to the stiffening of the workpiece, which is clamped at two points. The dimensions of the processed raw material are 300 × 30 × 50 mm, where 1.6 mm thick material was removed along the workpiece by milling in the same way in 8 passes. 2.2 Tool Used For this experiment in collaboration with SME Škutord.o.o. [9], an end mill is developed and it is made of hard metal, with TiAlN coating, which was performed by PVD process at the Jožef Stefan Institute [10]. The DIN 1836 standard uses N-mark of end mills for the fine machining of testing material group, and as the exact data on the cutting geometry are not clearly defined, the additional purpose of this experiment [11] is to check how much the selected cutting angles correspond to the group of materials. For the nominal diameter of the milling cutter, d1 = 16 mm was chosen, and other data on the values of the working length, the number of cutting edges and the cutting geometry are shown in Table 2. 2.3 Workpiece Material The testing material is structural steel, marked asEN S235 (DIN ST37), (P processing group of materials), and the chemical composition is given in Table 3. 2.4 Tool Machine Machine used for this experiment is Awea BM 850- vertical machining centre, year of manufacture 2006, shown in Fig. 1.
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Value
d1
16 mm (h10)
d2
16 mm (h6)
l1
82 mm (DIN 6527)
l2
26 mm
c
0,4 mm × 45°
ε
30°
No. of long teeth 2 No. of short teeth 2
αo
8°
γo
4°
αp
10°
γp
10°
Table 3. Chemical composition of S235 steel Element
C
Mn P
S
Si
Maximum rate (%) 0,22 1,6 0,05 0,05 0,05
Technical characteristics of the machine: • • • • • • • • • •
Work table dimensions: 1050 × 600 mm Maximum length of individual axes: X = 850 mm; Y = 600 mm; Z = 600 mm Work table weight: 850 kg Machine weight: 6500 kg Main spindle motor power: 7.5 kW (belt drive) Maximum spindle speed: 8500 rpm Maximum tool length: 250 mm Maximum tool diameter: d ≤ 75 mm Magazine tool storage capacity: 24 tools Maximum speed of feed movement: 15 m/min
2.5 Measuring Instrument Surface roughness is measured as the value of the arithmetic average roughness Ra, using the Hommel - Etamic W5 contact device.
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Fig. 1. Vertical machining centre Awea BM 850
Figure 2 shows the measurement procedure on the test workpiece, where 8 stepped surfaces were performed, each with processing modes according to the matrix of the test plan (Table 2). The measurement have been performed three times in order to reduce the possibility of measurement error.
Fig. 2. Measuring of surface roughness of workpiece
3 Results of the Experiment Table 4 shows the corresponding input values, cutting speed and feed speed with the obtained results of measurements (arithmetic mean of 3 measurement) of Ra . The results obtained by analysis in software Design Expert v12 are derived from the program interface and shown in Figs. 3, 4, 5 and 6, which is the statistical analysis of software.
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M. Kljajo and D. Šogorovi´c Table 4. Matrix of experiment - results No.
Real No. of measuring
Input factors vc
Output factor - Ra vf
1
5
160
600
0,158
2
7
301
600
0,122
3
6
160
1200
0,233
4
2
301
1200
0,218
5
4
230,5
900
0,148
6
1
230,5
900
0,144
7
8
230,5
900
0,156
8
3
230,5
900
0,146
Fig. 3. Results of analyse
The value of the predicted coefficient of determination R2 (“Predicted R2”) is close enough to the adjusted coefficient of determination (“Adjusted R2”), i.e. the difference is less than 0.2. The statistical significance of the mathematical model is determined on the basis of the values of the empirical F-ratio (“F-value”) and p-values in the ANOVA table shown in Fig. 4. The value of the F-ratio of 82.39% for the selected model indicates the importance of the model, i.e. there is a chance of 0.06% to achieve such a large F-value due to external influences. The value of p (“p - value”) determines the significance of the model and individual factors. If the value of p is less than 0.05 the factor is significant. The results show that both factors, cutting speed and feed speed are significant.
Fig. 4. ANOVA table
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Fig. 5. Coded and de-coded model of roughness
According to the results shown in Fig. 5, the coded roughness model is: Ra = 0, 1828 − 0, 0128A + 0, 0427B
(3)
De-coded roughness model is: Ra = 0, 096186 − 0, 000181vc + 0, 000142vf
(4)
As seen from the results of experiment, tested end mill achieved excellent results in surface quality even at the lowest cutting speeds and highest feed speed. The highest measured value of Ra is 0.233 µm, while the lowest measured value is 0.122 µm. Such values correspondent to N3 and N4 quality classes, which shows the excellence usability of this end milling cutter in fine machining conditions. Figure 6 shows a threedimensional diagram of relation of input factors on the surface roughness, generated in a computer program Design Expert v12.
Fig. 6. Relation of Ra on input factors (cutting speed and feed speed)
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4 Conclusion There are many factors with significant influence on roughness of machined surface but one of the most important are technology parameters. The performed experiment shows that the two elements of the cutting process, cutting speed and feed speed have significant influence on roughness. As is already known from the theory, this testing proves that the less roughness means less feed speed and higher cutting speed. This conclusion is reliable only for this material, used tool and the other testing conditions and equipment which were being used in this experiment. Future research will be focused on the other materials of workpieces as well as on the other milling cutters, and this paper is one small step in the future studies about correlation of end mill geometry and influence of technology parameters on surface roughness in fine milling machining. Acknowledgment. The authors wish to thank the SME Škutord.o.o. for support of performing of student praxis in this SME. This support helped student author to perform the experiments in master thesis in order to finish his master degree study.
References 1. Kalajdži´c, M.: Tehnologijaobraderezanjem, University of Belgrade, Faculty of Mechanical Engineering, Belgrade (1998) 2. Rebec, B.: Reznialati, Tehniˇckaknjiga, Zagreb, Croatia (1972) 3. United States Cutting Tool Institute, Metal Cutting Tool Handbook, Industrial Press Inc., New York (1989) 4. Smith, G.: Cutting Tool Technology. Springer, London (2008) 5. Balogun, V.A.: Effect of cutting parameters on surface finish when turning nitronic 33 steel alloy. Int. J. Sci. Eng. Res. 6, 1–9 (2015) 6. Kalpakjian, S.: Manufacturing Processes for Engineering Materials. Addison Wesley Publishing Company, Sydney (1997) 7. Jozi´c, S.: Višeparametarsko modeliranje i optimiranje tvrdog glodanja – doktorska disertacija, University of Split,Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Split, Croatia (2012) 8. Altintas, Y., Engin, S.: Generalized Modeling of Mechanics and Dynamics of Milling Cutters, University of British Columbia, Vancouver (2007) 9. www.skutor.ba 10. www.ijs.si/ctp 11. Kljajo, M.: Konstrukcijavretenastihglodala. Diploma paper, University of Mostar, Faculty of Mechanical Engineering, Computing and Electrical Engineering, Mostar, BosniaHerzegovina (2019)
The Electro-Pneumatic System as a Cyber Physical System: The Concept Elvis Hozdi´c1,2(B) and Zoran Jurkovi´c3 1 Department of Control and Manufacturing Systems, Faculty of Mechanical Engineering,
University of Ljubljana, Ljubljana, Slovenia 2 Kranj School Centre, Kidriˇceva cesta 55, 4000 Kranj, Slovenia 3 Department of Industrial Engineering and Management, University of Rijeka,
58000 Rijeka, Croatia
Abstract. The implementation of the new industrial revolution named - Industry 4.0 depends on a series of new and innovative technological achievements, most of which are applied in manufacturing domain. Progress in the field of informationcommunication technology (ICT), especially in the field of internet, enabled thedevelopment of the new manufacturing system models through the transformation of traditionally isolated, hierarchical structures into open and distributed networked structures. Our personal view on the conception and evolution of manufacturing systems structures from the traditional manufacturing systems towards advanced manufacturing systems, such as the cyber-physical systems (CPS) in the domain of electro-pneumatic systemsis presentedin this paper. This paper presents the model of the electro-pneumatic system (EPS) in a spirit of the cyber-physical systems. The development of a cyber-physical based EPS model represents an evolution extension of the electro-pneumatic systems from traditional systems into distributed networked systems based on the three key enablers of Industry 4.0: connectivity, digitalization and cybernation. Keywords: Connectivity · Digitalization · Cybernation · Cyber-physical systems · Electro-pneumatic systems · Industry 4.0
1 Introduction Faced with a comprehensive globalization manufacturing companies are trying to be competitive, but also continuously increase their competitiveness in order to be successful and maintain its place in the global economic market. A manufacturing company can achieve this position with continuous improvement of its manufacturing systems. The rapid development of technology and science that accompanies technology opens up new horizons for the successful management of new complex distributed production systems. Today’s market calls for new demands, complex and highly advanced requirements to be met and thereby achieve their goals, to be successful. These circumstances lead us © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 239–250, 2021. https://doi.org/10.1007/978-3-030-75275-0_28
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to actions that will yield better and more successful business, and that drive us to continuous improvement of our production systems, primarily for the implementation of new technologies, new technological solutions and new knowledge. With new technology it is possible to be a part of the world’s global mega trends. For such activities, above all it is necessary to confront the systems that surround us, technological developments that surround us, conceptualize them and manage them. This leads us to continuously study and research implementation of new approaches, methods, tools and concepts for an effective understanding of interactions that take place within the advanced manufacturing complex distributed systems in a network environment, based on connecting real – physical components with the digital – cyber world. Today, due to the Industry 4.0 challengesand recent developments of the informationcommunication technologies (ICT), manufacturing enterprises tend to structure their manufacturing systems in a spirit of a cyber-physical system (CPS) [1]. Modern manufacturing enterprises must be focused on sustainable, agile, networked, service-oriented, green, and social manufacturing practices, among others [2]. Industry 4.0 stands for a new way of organization and control of complete valueadding systems [3, [4, 5]. Industry 4.0 is driven by new discoveries of sciences, enriched knowledge, new and enhanced materials, and technologies, especially in the field of ICT. Besides, novel organizational forms and innovative managerial principles of emergence, self–organization, learning, open innovation, collaboration, and networking of humans and organizations are becoming the key elements of the next generation manufacturing systems [6]. The term “cyber-physical systems”, coined in 2006 in a high-level working group [7] composed of selected experts from the USA and European Union, advocates the co-existence of cyber and physical elements with a common goal. Embedded systems have been developed over the past decades, however CPS explicitly pose a focus on the integration of computation with physical processes [8]. Current approaches have many limitations in the form of barriers to be overcome, particularly in terms of exchange of information through existing interfaces on cyber and physical spaces, primarily those that are exchanged between cyber and physical spaces on the one hand and the biological, human, humane world on the other. As a result of information exchange, interaction among participants of sociological and technical systems are unpredictably growing, in relation to the complexity of manufacturing systems themselves. The successful mastering by reducing this complexity, makes it possible to achieve perceptible results in business complex production systems. This is possible by the new technology, which we need to know, implement and structure adequately. However, in order to develop and implement Industry 4.0 principles, a transformation of manufacturing structures from the traditionally isolated, hierarchical structures into open and distributed networked structures is needed. The foundations of this transformation are the three key enablers of Industry 4.0: connectivity, digitalization and cybernation [6]. Today, in modern manufacturing, the pneumatic systems (PS) and the electropneumatic systems (EPS) provide a safe and reliable opportunity to automate production according to Industry 4.0 principles. The problem of adapting the old PS and EPS to the modern requirements are described in the paper [9].
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In this context, the transformation of PS and EPS from the traditionally structure into distributed networked structures will be presented in the next. The new structures of PSand EPS will be based on the key enablers of Industry 4.0. Such a transformation will pave the way for digitalization and cybernationof a PS and an EPS. The aim of this paper is modelling of a PS and an EPS in a spirit of a CPS. The paper first presents the EPS with its electro-pneumatical control system and the cyber-physical systems. Next, it presents the conceptual model of the electro-pneumatic system in the form of CPS. Further on, the conceptual model and structure of an EPS as a CPS are presented.
2 Literature Review 2.1 Pneumatic and Electro-Pneumatic Systems In different sectors of the modern industries, pneumatic technology is used as means of work place mechanization and automation where a major part of manual and tedious work may be supplemented by pneumatic controls for quick and economic production [10]. A pneumatic system (PS) is a system that uses compressed air to transmit and control energy [11–13]. It is a structure of interconnected components using compressed air to do work for automated equipment. The PS are constituted by information elements, work elements and signaling elements. The transferring of energy in the PS must be controlled. Pneumatic controls consist of signaling elements, control elements and work input. The signaling and control elements, so called valves, modulate the execution phases of the work elements [14].The control of pneumatic components by electrical impulses is known as electro-pneumatics [15]. According to [15], “electro-pneumatics is successfully used in many areas of industrial automation such as production, assembly, packaging systems etc. Such systems are driven by electro-pneumatic control systems”. Kumar and Jay [16] defined electropneumatic system (EPS) as an integration of pneumatics and electrical technologies. The pneumatics elements of the EPS are actuators (e.g., cylinders, motors, etc.) while sensors and control elements (e.g., valves, etc.) are electric elements. In industrial automation systems, the EPS plays very significant roles because of the advantages of easy maintenance, cleanliness, low cost of production, availability and low energy consumption [17, 18]. The control systems for EPS are mostly implemented by using Programmable Logic Controller (PLC) [19–21]. According to [9], “the use of electric components opens the way for applying the programmable logic controller (PLC) that allows implementing more advanced control strategies”. In [22], Bolton defined PLC as a specialized form of microprocessor-based controller that uses memory and can be programmed to store instructions and can be used to implement functions such as logic, sequencing, timing, counting and arithmetic to control machines and processes. The example of an EPS structure is presented in Fig. 1. The structure of the EPS consists of elements: 1) actuators (e.g., acting cylinders), 2) control elements (e.g., valves), 3) electric proximity switches, 4) relays, 5) programmable logic controller (PLC), 6) compressed air source, and 7) power supply.
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Fig. 1. The block diagram of the EPS with the PLC
The use of PLC in the EPS enabled more advanced control of EPS and their connection into a network structure (network of things).The example of the schematic circuit diagram for an EPS with pneumatic double acting cylinder and PLC is shown in Fig. 2.
Fig. 2. The example of a schematic diagram for pneumatic double acting cylinder with the programmable logic controller
In the paper [19], design and realization of remote control system that is used for control of movement of pneumatic cylinders are considered. The control is solved using
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the microcontrollers with Wi-Fi communication. Suggested by [19]: “With very small changes in the software it is possible to achieve that the client is another microcontroller, which creates all the prerequisites for direct communication between two machines (machine to machine communication – M2M communication), which is one of the basic requirements in the Industry 4.0”. 2.2 Cyber-Physical Systems Cyber-physical systems were first defined by Lee [23] as follows: “Cyber-physical systems (CPS) are integrations of computational and physical processes. Embedded computers and networks monitor and control of the physical processes, usually with feedback loops in which physical processes affect the computations and vice versa”. In the paper [24], Baheti and Gill defined CPS as transformative technologies for managing interconnected systems between its physical assets and computational capabilities. Suggested by [25]: “Cyber-physical systems (CPS) are systems of collaborating computational entities which are in intensive connection with the surrounding physical world and its on-going processes, providing and using, at the same time, data-accessing and data-processing services available on the internet”. According to Leita˜o et al. [26] CPS constitutes a network of interacting cyber and physical elements aiming a common goal. The information flow between the cyber and the physical word is presented in Fig. 3.
Fig. 3. The flow of information between the physical and cyber world [27]
The CPS architecture for Industry 4.0 is proposed in [28]. In the paper [29], Bagheri et al. presented the CPS architecture for self-aware machines in Industry 4.0 environment. Fourth prototype implementations for industrial automation based on CPSs technologies is described in [26]. Jazdi [30] defined the main characteristics of a CPS in the context of Industry 4.0 and presented the connection between a CPS, smart sensors, actuators, and the Cloud. Also, the characteristics of CPS are outlined together with those of the Internet of Things (IoT), Internet of Service (IoS), big data, and Cloud technology in the paper [31]. The potential and benefits of CPS to change all aspect of industry sectors are enormous. Today, many industries have initiated projects in the CPS domain [32]. Zhong
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et al. [32] presented a list of typical applications of CPS in diverse fields such as medicine and healthcare, biology, civil structures, autonomous vehicles, power distribution and intelligent manufacturing. In the paper [33], the authors presented the application of CPS into five levels: product level, level of production line/work station, supply chain level, device/machine level, and facility level. According to Schuhmacher and Hummel [34] the emergence of CPSs and crosslinked CPPS will lead to a fundamental restructuring of manufacturing work and logistic systems, and will require new forms of human-machine interaction. On this basis, the generic conceptual model of a CPPS is developed in the paper [6]. In this paper, the general conceptual model of CPPS [6] will be the base for the design of a new conceptual model of CPS-based an electro-pneumatic system.
3 Model of an Electro-Pneumatic System in the Form of a Cyber-Physical System The conceptual model of an electro-pneumatic system in the form of a cyber-physical systems (EPCPS) is shown in Fig. 4. The model consists of three elements: 1) human Subject as a social element, 2) the electro-pneumatic cyber system (EPCS) as a cyber element, and 3) the electro-pneumatic physical system (EPPS) as a physical element. The connectivity between these elements is enabled via the corresponding communication interfaces. The Subject has the corresponding relations with the business and social environment, the EPCS with the cyber environment and the EPPS with the physical environment. The new element of the developed model is the electro-pneumatic cyber system (EPCS). According to [6], the infrastructure of the EPCS enables vertical connectivity of the EPS with other superior systems in manufacturing and the horizontal connectivity of the EPS with other manufacturing structures in the network structures such as Internet of things, Internet of service, and production network. Also, the infrastructure of the EPCS enables connecting the physical and social elements in electro-pneumatic systems. This enables the possibility of remote control of the EPS. The elements of the EPCS enable the management and control of the EPS in real time, through the realization of the digitalized and cybernated functions of the cyber-physical based EPS. The digitalized functions are functions that are executed in digitized processes and are executed fully automated. This means that digitization enables the transformation of many information processes in the EPS. In addition to pure information processes in the EPS, we also have many different processes that we cannot digitize. These are processes of material transformation that are analogous in nature (e.g., material processing, assembly processes, logistics processes etc.). For the implementation of these processes are necessary physical elements (e.g., machine, actuators, sensors, human, etc.) as well as computer elements (e.g., programmable logic controllers, digital processors, software, data and knowledge bases, etc.). Today’s EPS therefore consist of several physical and digital elements that are interconnected into a hybrid of the analog/digital world. This, in turn, paves the way for
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Fig. 4. Conceptual model of the EPCPS, adopted according to [6]
the cybernated functions in the EPS. The cybernated functions are functions that are executed in a hybrid of the analog/digital space (their inputs are analog and digital in nature).the transformation of traditional EPS functions into the cybernated functions requires vertical and horizontal integration of different environments. This connectivity of the social, cyber and physical elements of the EPS is a key element of Industry 4.0 on which the developed EPCPS conceptual model is based. In the next, the developed EPCPS conceptual model is presented on the example of EPS for implementing processes of assembly and disassembly.
4 Example of the Electro-pneumatic System in the Form of a Cyber-Physical System The application of the CPS based EPS is outlined next. For the example of the electro-pneumatic system in the form of a cyber-physical system is elaborated on an assembly/disassembly cell (MAP 201 unit [35]) from SMC manufacturer.
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4.1 Electro-Pneumatic System MAP201 Electro-pneumatic system in the form of an assembly/disassembly cell MAP 201 provides an automated process that uses a variety of technology to perform it operation. This system includes the following automation technologies: a) regulation and filtering of pneumatic supply, b) pneumatic flow control, c) pneumatic direction control, d) pneumatic actuators, e) electrical control switches and sensors, f) electrical solenoids, g) DC power supply, and h) programmable logic controller. The structure of electro-pneumatic system MAP 201 is presented in Fig. 5a.
a)
b)
Fig. 5. The electro-pneumatic system MAP 201 [35]
The process of assembly/disassembly in MAP 201 unit is organized as follows. A gravity feeder houses the parts in a column (1), see Fig. 5 and Fig. 6. Each part has a non-symmetrical interior housing and is ejected by a pneumatic cylinder A (2). The correct orientation of the part is verified using a cylinder with a plunger C (3). After verification, an oval section pneumatic cylinder B (4) moves the workpiece to the final position. Otherwise, a single acting cylinder D (5) removes the part via the evacuation ramp. The electro-pneumatic diagram of an electro-pneumatic control system for MAP 201 unit is show in Fig. 5b. The sequence for electro-pneumatic system MAP 201 could be written in symbolic form as: A+, A−, B+, B−, C+, C−, D+, D−. 4.2 Cyber-Physical Based Model of Electro-Pneumatic System MAP201 The model of the electro-pneumatic system MAP 201 in the form a cyber-physical system (EPCPS MAP 201) is shown in Fig. 6. The EPPS of MAP 201 is connected to one or several logistic systems (LS), through which input and output materialflows are regulated. EPPS of MAP 201 and LS are
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Fig. 6. CPS based model of electro-pneumatic system (EPCPS MAP 201)
in physical space connected with material flow as well as Field Bus and Profibus communication channels. The communication of EPPS of MAP 201 with the EPCS of MAP 201 is enabled through the smart sensors and communication interface (e.g., a programmable logical
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controller, etc.). To connect the EPPS of MAP 201 in the EPCS of MAP 201, the multiagent system (MAS) has established and applied modern communication technology based on TCP/IP protocols and 802.15.4 standard for wireless local area network. Modern ICT enable real-time data acquisition and transferring of information and data from the physical space in the cyber space to allow for the automatic analysis of the system operation through various inputs and outputs, together with an electrical control system. The exploitation of such information and data in the EPCS of MAP 201 provides access to and distribution of all relevant information on the EPCPS MAP 201 in real time. The collected data have the role of support in the implementation of the digitalized and cybernated functions of each EPCPS MAP 201 as well as information support for the integration of the EPCPS MAP 201 into network structures. The communication in network structures enables EPCPS MAP 201 decisions without human intervention and new digitized and cybernated functions that will increase EPCPS MAP 201 efficiency, flexibility and responsiveness.
5 Conclusion Cyber-physical systems and an advanced manufacturing technology opennew possibilities and potentials in the management and control of electro-pneumatic systems. The paper introduces the new conceptual model of EPS in a spirit of the CPS. Based on the developed EPCPS concept enabled the integration of physical, cyber, and social elements of the electro-pneumatic system in the functional environment. The main advantage of a new model EPS is (1) that the elements of the cyber system of the EPCPS enable the management and control of EPS in real time, through the realization of the digitalized and cybernated functions of the EPCPS, and (2) connectivity of EPCPS with other elements and systems over the network structures. The implementation of the EPCPS concept in real industrial environment is a challenge for further research, thus contributing to research in the direction toward Industry 4.0.
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Role of Industry 4.0 in Albanian Industry Transformation: An Integrated Understanding of Industry 4.0 Ilo Bodi(B) , Erald Piperi, Eralda Xhafka, Jonida Teta, and Merita Kosta Faculty of Mechanical Engineering, Department of Production and Management, Polytechnic University of Tirana, 1001 Tirana, AL, Albania [email protected]
Abstract. Nowadays, industrial conditions change quickly due to the influence of globalization as well as sociological, technological, economic, and political factors. On top of that, industries have revolutionized, and continuous upgrades has taken place to strengthen its functionality of resources sharing and integration capabilities of functional units. The goal of this article is to understand and explore how adoption of Industry 4.0 technologies will impact and transform the functions of a company. For this, the index analysis helps us to identify the current potential of the country. Hence, knowing the current challenges and opportunities of the country in relation to Industry 4.0, helps us to devise a realistic implementation model. The study clears the overall picture of Industry 4.0 in the textile industry. This helps, clarifying the concept in a country where technological culture is in low terms, and in a sector where changesare required. Keywords: Industry 4.0 · Industry 4.0 adaption · Intelligent factory · Basic technology · Chain of global value
1 Introduction The boom of global “industrialization“ influences all competitive dimensions of a company by digitizing and revolutionizing the operating approach. Hence, the traditional model is substituted for emerging model, which could be called integration of industrial chain, or industrial revolution. Industry 4.0 or the Fourth Industrial Revolution can be defined as the concept of an integration between Information and the Digital Revolution [1]. The term is the generation of three previous revolutions, with a particular focus on increased productivity and efficiency. The primary idea has been presented in Hanover’s 2011 Congress, treated as a strategic programme to develop advanced production systems [2]. Among other things, this new phase of the industry requires a socio-technical evolution of human role in all business ecosystem modules. The Industry 4.0 brings the concept of automation far ahead. It creates a full digitalisation and a transformed automation process, in all its constituent stages, concluding in an “intelligent factory”. Exploring Industry 4.0, may help the engineers and entrepreneurs to resolve high © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 251–259, 2021. https://doi.org/10.1007/978-3-030-75275-0_29
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uncertainties and gain more competitive advantages. Technology architecture [3] of the Industry 4.0 has a huge potential to reshape the way companies operate. Based on their main objective, we have two technological divisions: 1. Front technology, which considers four dimensions (intelligent production, intelligent product, intelligent supply chain and intelligent work). The central dimension considered intelligent production, while other dimensions are related to it. Each dimension adapts to other sub technologies creates added value. 2. Basic technology, which supports the other intelligent dimensions discussed above. Such technology includes: Internet of Things (IoT), Big Data Cloud Services, Robotics, Artificial Intelligence (AI), Analytics, Additive Manufacturing, Digital Twins, Added Reality, 3D Printers. These technologies are considered basic, as influential integration dimensions are present in them. Industry 4.0 will lead to virtualization and modularization of production process and supply chain, achieving flexibility and personalization of production [4] based on software systems. It is not surprising that toward developing a fully functional Industry 4.0 has been a centre of focus by both firms and researchers. In order to develop a case study, which evaluate the potential of Albania in adapting Industry 4.0, the use of nine indexes round up analytical treatment better. Index analysis is widely acknowledged to play a vital role in the opportunities of the countries to adapt Industry 4.0. The process of technological standardisation within the business ecosystem is identified as the backbone of Industry 4.0. Index results unfold value benefits in further implementation directions. Albania, as a less industrialized country (based on the development in different sectors, the current efforts for improvement, index data), shows significant problems, especially in the textile industry sector. Textile industry must be aware of the new challenges and respond with a judicious action in order to reduce production cost, improve manufacturing productivity, promote industrial growth, change the labour force structure and ultimately change the competitiveness of the company and the region. The following implementation model reveals the transformation of the textile industry in revolutionary terms, adapting to the reality of the country and the internal conditions of the company. It presents a real and appropriate model, which enables a new culture and spirit of industrialisation. Meanwhile, all the information obtained helps the institutions, companies and all other constituent actors of the Industry 4.0 concept.
2 Methodology This article will employ a multiple case study as research method with holistic approach, to conduct an in-depth study of the Industry 4.0 adaption model. In this context, the individual case will consist in a implementation model that will be studied. Methodology is based on research questions, literature review and data analysis. To successfully understand and find the best solution, the research work is focused on the following steps: 1. The first phase is the literature review of Industry 4.0 and company needs and what we want to improve.
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2. The second phase, analyses the indexes that best identify the Industry 4.0 potential at country level. The data is collected by open sources, while the results released are presented in practical form, as applicable solutions to our company case. 3. The third methodological phase is based on deductive research for building an implementation model, which highlights the role of the Industry 4.0 throughout the business area. Technology in itself cannot achieve results if not implemented correctly. “Industry 4.0” models would boost industrial upgrading to realize intelligent and flexible manufacturing for mass customization. Business executives will find this article informative as they contemplate whether to invest in and outsource to other countries. In addition, policymakers will learn about the challenges and opportunities of Industry 4.0 in Albania manufacturing environment.
3 Industry 4.0 Adaptation Starting from the analyse of nine global indexes, potential and adaption, specific treatment will be developed to shape the vision of Industry 4.0. These will be assessed for Industry 4.0 according to their investment needs and strategic value input. For implementation model treatment, recognition with the country’s overall technological potential is a very important phase. Index techniques, would be a necessity for decision support, although only indexes are easily found. Index analysis best covers strategic framework of technologies. The power of analyse, refers to the performance of Albania, in accordance with Industry 4.0. The results obtained by “International Research Institutions” in studying of the nine indexes to identify Industry 4.0 is very helpful. In this purview, the treatment of indexes is presented as follows: The Global Innovation Index (GII) [5]. Allows us to analyse the potential, based on two main components: innovation and production of innovation. Referring to the total assessment (1–100), the GII annual total value for Albania is 27.12. The Logistics Performance Index (LPI) [6]. Logistic operation is included in the framework of regulatory services, securing transport infrastructure, enforcement of audits (particularly for international goods) and boosting the quality of Public-Private Partnership. In its assessment of 1–5 Albania receives its annual rating of 2.62. The Global Enterprise Index (GEI) [7]. The focus on production, does not generate the total view of Industry 4.0 concept. The Enterprise Index, helps our treatment approach for a deeper focus. Entrepreneurship in our country can be measured at levels such as: entrepreneurial attitudes, entrepreneurial skills and entrepreneurial aspirations. Integration of such levels concludes at a low level of entrepreneurship (based on the latest annual assessment 22.5), though recent years the health of the entrepreneur’s ecosystem is on a steady rise. Human Development Index (HDI) [8]. The index demonstrates the country’s human development status through components such as: life expectancy at birth, expected years
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of schooling, average years of schooling and gross national income per capital. Our country, relating to the statement on the overall score of 0.791 at the range of 0–1, is represented by governance at acceptable stability rates, average health access, development not in emphasised dimensions of unification and education on average levels. Environmental Performance Index (EPI) [9]. Reflects the vitality of the ecosystem, and serves as an instrument in adopting Industry 4.0. Based on the overall assessment, Albania reflects an average score (49 from the range 0–100). Industrial Production Index (IPI) [10]. Progress towards Industry 4.0, among others, requires a constant and adequate production environment. In monthly terms Albania presents a significant decline in industrial production, (-22) justified by the pandemic situation. Industrial Competitiveness Index (CIP) [11]. At a range of 0–1, Albania is estimated at 0.008, which means significant restrictions on industrial management, and policies at modest levels of adaptability. Structure and Drivers of Production [11]. Both factors are part of “readiness factor”, which represents strategic importance in implementation. Therefore, to successfully master Industry 4.0 readiness, calculation of upper factors presents strategic importance. Interestingly, there has been a quick escalation in the number of Industry 4.0 readiness models in the recent few years. However, it has also been discovered that a large number of academic Industry 4.0 readiness models are not known in Albania industry, as they are less pragmatic in terms of fast-moving objectives of industry.
3.1 Analytical Results The obtained results will highlight the capability of Albania in adapting Industry 4.0. The adaption model was affected by external and internal factors. The acquired results unfold how governments can address issues related to Industry 4.0. In addition, international trade, partnership with high-tech companies, and advancement in technical schools would represent adequate intensification for a digitalised ecosystem approach. Dealing with Industry 4.0 as a socio-technological challenge attaches particular importance to the holistic integration of production and society. In that context, the needs for change in Albania consists on: the propriate basis of knowledge on the operating market-operation between research-development institutions and focus on obstacles. While further adaptation opportunities refer to: capacity in internal dimensions, influence of political instruments, obtaining a resilient environment towards changes and awareness at a trade level.
4 Implementation Model: DBS Group Step 1: Readiness Factor Calculation Readiness factor is in most cases defined as a stage between four industrial revolutions
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[12]. This can be understood even as the decision-making process because management has to decide whether their company is ready for the complete automatization or not. In general, are known two calculating methods: • External method • Internal method External method allows us to calculate the readiness factor according to a national adaption [2]. Analysis in Albania has been made in regarding of digital adaption and automation in production sector, technology, logistics, quality control, and others. In most cases readiness factor according this method, consists of two elements: structure of production and drivers of production. In parallel, structure of production consists of two other dimensions: complexity (is used to analyse how country’s different types of knowledge and technology are combined with each other in the manufacturing sector) and scale (Manufacturing Value Added). According to “World Economic Forum” [13], Albania has the following results: 1. Complexity = 3.9 2. Scale (manufacturing addedvalue) = 1 Total structure of production referred to the weight of above elements results: Structure of production = complexity (60% × 3.9) + scale (40% × 1) = 2.74. Similarly, we act for drivers of production. The result of its six constituent factors, is provided: • • • • • •
Technology and innovation = 3.4 × 20% = 0.68 Human capital = 4.6 × 20% = 0.92 Global trade and investments = 3.7 × 20% = 0.74 Institutional frame = 4.7 × 20% = 0.94 Steady production = 6.2 × 15% = 0.93 Request environment = 3.2 × 5% = 0.16
Drivers of production = 0.68 + 0.92 + 0.74 + 0.94 + 0.93 + 0.16 = 4.07 (Table 1). Step 2: Business Field Planning At this stage we discuss more closely the needs that are addressed for preliminary solutions major changes are required for DBS company so it could adjust to the concepts of Industry 4.0. Focused on segment techniques, mass personalisation, specific advancement practices, will help DBS company provide solution packages in all modules. Step 3: Prototype Development The implementation model for the DBS company has as primary goal the intelligent factory. Hence, prototype development will address previous changes in production activity. DBS group follows a technological flow for obtaining the final product: “raw-material”
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warehouse, prototyping and cutting department, production department, control and packaging, finished products warehouse. The prototype is based on avoiding the problems that are most encountered in the production activity and is presented modest both in financial and operative terms. DBS company operates with 16 production lines, while the prototype design is based on primary changes that will include only one production line. In function of the second implementation step, where we defined the objectives and challenges, and in focus of the production activity problems we devise the changes that will include a production line. This step is included in a more modest funding framework, and serves mostly to assess the continuity of implementation. Based on the real issues addressed, and the points mentioned above, the prototype includes the following changes:
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1. Replacement of current machines (for one production line). Since the next steps require a more sophisticated technology, it would be a worthless investment if the intervention is not carried out initially in the element that brings more breakdown both in terms of production and management. 2. Installation of sensors in each changed machine. The foundation of Industry 4.0 in the textile industry is in particular the integration of sensors. Through these sensors installed in new machines, the company will gain valuable data in terms of management.
Step 4: Prototype Evaluation In this step prototypes considered above, are subject to specific analysis and evaluations. Estimates are examined at the moment when changes in total ecosystem performance are noticed. The success of this step creates real opportunities for integration between technological innovation and human resources. Step 5: Prototype Replication The changes that follow this phase have a substantial effect on traditional roles within the organisation and better integrate existing technologies. During Cloud ERP implementation software, it is important the readiness of all management levels to adapt and use it. The inclusion of the Cloud ERP platform enables a general development framework on IoT within the enterprise (Fig. 1).
Fig. 1. IoT adaptation in the value chain for DBS company
Step 6: Total Spread The final stage of Industry 4.0 implementation, consists in digitizing the entire value chain process, and adapting other strategic technologies. The Industry 4.0, for DBS company is represented in addition to the above digital changes, also by the following technologies: a) Completing such a digitalization framework can be accomplished with the implementation of Big Data software knowing as Analytics as a Service (AaaS). Such data analysis enables efficient decision making and a proper functional mechanism.
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b) The Industry 4.0, represented by the above technologies, can be quite well complemented by the addition of technologies such as: augmented reality andtransportrobotics (Fig. 2).
Fig. 2. Communication platform/IoT for DBS Group
5 Conclusion The textile industry is one of the most potential manufacturing sectors in Albania.This article presents an overview of Industry 4.0 adaption as an implementation model for textile industry. The above treatment enabled us to recognize Industry 4.0 concept in another dimension. Starting from the generic meaning of Industry 4.0, we have tried to adapt it to a less industrialized country like Albania. Through analysing the potential and country adaptation, we devised improvement opportunities and concrete plans, which are valid for different manufacturing areas. Based on our limitations in this research paper, Industry 4.0 concept has to be explored and applied also in low-level industrialised countries.
References 1. Salkin, C., Oner, M., Ustundag, A., Cevikcan, E.: A Conceptual Framework for Industry 4.0. in Industry 4.0: Managing The Digital Transformation. Springer Series in Advanced Manufacturing. Springer, Cham (2018). https://doi.org/10.1007/978-3-319-57870-5_1 2. Hizam-Hanafiah, M., Soomro, M.A., Abdullah, N.L.: Industry 4.0 Readiness Models: A Systematic Literature Review of Model Dimensions. Information 2020, 11, 364 3. Lee, J., Bagheri, B., Hung, K.: A Cyber-Physical Systems architecture for Industry 4.0-based manufacturing systems. Manuf. Lett. 3, 18–23 (2015) 4. Brettel, M., Friederichsen, N., Keller, M., Rosenberg, M.: How virtualization, decentralization and network building change the manufacturing landscape: an industry 4.0 perspective. International Journal of Mechanical, Industrial and Aerospace Sciences: 7.0 (1) (2014) 5. https://www.globalinnovationindex.org/analysis-indicator 6. https://lpi.worldbank.org/international/global/2018.%202019
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7. https://thegedi.org/global-entrepreneurship-and-development-index/2019humandevel-opm entindexranking 8. http://hdr.undp.org/en/content/latest-human-development-index-ranking 9. https://epi.yale.edu/epi-results/2020/component/epi 10. https://www.federalreserve.gov/releases/g17/current/ 11. https://stat.unido.org/cip/ 12. Siau, K., Xi, Y., Zou, C.: Industry 4.0- challenges and opportunities in different countries. Cutter IT J. 32, 6–14 (2019) 13. https://www3.weforum.org/docs/FOP_Readiness_Report_2018.pdf
Challenges of Albanian Companies for Sustainable Development in the Era of Industry 4.0 Irma Shyle(B) , Eralda Xhafka, and Jonida Teta Faculty of Mechanical Engineering, Department of Production and Management, Polytechnic University of Tirana, 1001 Tirana, AL, Albania [email protected]
Abstract. Many companies have implemented technology in their production or service delivery processes. In this way, companies today see Industry 4.0 as a necessity, because it provides companies with a competitive advantage, quality product, speed and better fulfillment of customer needs and desires. However, even though companies today are using Industry 4.0, there are still problems such as: high level of resource consumption, high level of pollution, environmental changes, high unemployment rate, etc. Companies today face the pressure and the necessity of implementing sustainable development. This pressure is exerted by the community, the government and even by the universe itself. A sustainable industrial development strategy should aim to achieve the integration of environmental concerns and sustainable development in industrial policy, thereby promoting environmental protection, competitiveness, innovation and employment. In the long term, sustainable industrial development can only be achieved through the integration of all three pillars of sustainable development – economic, environmental and social. Sustainable development is not only environmental protection, it is a process in which different policy areas such as economics, trade, energy, agriculture, industry, etc., are formulated in order to create a development that is economically, socially and environmentally sustainable. The purpose of this paper is to highlight the challenges faced by Albanian companies for the implementation of sustainable development. Through factorial analysis, this paper aims to build the model by identifying the factors that are most important in the implementation of sustainable development in Albanian companies. Keywords: Industry 4.0 · Sustainable development · Albanian companies · Challenges
1 Introduction Sustainable development is defined in different ways but the most well-known and accepted definition so far is: “Development that meets the needs of the present, without compromising the ability of future generations to meet their needs” [1]. So sustainable © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 260–269, 2021. https://doi.org/10.1007/978-3-030-75275-0_30
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development is not only the protection of the environment, but also a new concept of economic growth, to provide justice and opportunity for all, without destroying the planet’s natural resources and capacity. The economy is a system of human society which is in itself a system of the totality of life on Earth, and, there is no system that can expand beyond the capacity of the general system of which it is a part [2]. Sustainable development represents attractive opportunities for sustainable economic development that does not exceed the economic, socio-cultural, environmental carrying capacity of the land [3]. Globalization has increased the degree to which organizations rely on each other to deliver products and services in the marketplace. Improvements in technology, communication and distribution channels have changed the number of participants and the physical distance between partners in the supply chain. This means that the viability of any single organization can now have an impact on the viability of other participants in the supply chain. Sustainable development is not only environmental protection, it is a process in which different policy areas such as economics, trade, energy, agriculture, industry, etc., are formulated in order to create a development that is economically, socially and environmentally sustainable [4]. Companies striving or seeking to become sustainable businesses need to understand that the concept of sustainability must be implemented in each objective of each of their departments. In other words, consistency requires to think that everything is related to something else and nothing exists in isolation. Every person, every department, every business, every industry and every society are interconnected in a way. Therefore, it is understandable that every part of the company contributes to help it to become a sustainable business. Ranging from day-to-day operations, research developments, information management system, technology, human resources, finance and marketing department are all linked to sustainability in a variety of ways. Sustainability is a whole company philosophy. Tonelli et al. [5] suggest that industrial organizations that predict and plan for a sustainable future are likely to survive into the next generation. Learning how to use significantly less material and energy to create the same or better customer value, while creating little or no waste is not only a sensible long-term strategy but also a compelling argument in today’s volatile world. The industrial sector has traditionally seen an important trade-off between eco-friendly improvements and economic development. The first step in transforming any current manufacturing environment into an ‘intelligent factory’ requires vertical and horizontal integration within the company. That is, integrating not only all the related production areas from different facilities, but also, in turn, the links with distributors and customers through information and communication technology (ICT) platforms and applications that integrate production and information systems, making global supply chains more transparent and helping to reduce the use of packaging, waste and energy [6]. Many organizations that have not adopted information technology (IT) are struggling to survive. In business today, regardless of their sectors and activities, entities have the same view concerning the future and do not want to be taken by surprise. Therefore, every sector is adopting Industry 4.0 due to the capabilities of the quality achieved in product customization. Industry 4.0 provides new features and possibilities in manufacturing in two main aspects: the value added to the final customer and production process capabilities [7]. Stock and Seliger [8] have argued that industrial value should
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be sustainability-oriented and Industry 4.0 provides tremendous opportunities to achieve this sustainability. Challenges Encountered in Implementing Sustainable Development The challenges and opportunities associated with the implementation of Industry 4.0 are still uncertain, and the technologies associated with this industry in terms of environmental sustainability have not been adequately explored because these are still new technologies [7]. The challenges identified in various studies for the implementation of sustainable development are: Information and Time. Shaper [9] identified in his study that companies lacked information about sustainable development while Revell & Blackburn [10], identified that companies lacked knowledge about laws. Lack of staff time in the company is also mentioned as a challenge [11]. Cost- previous research on barriers faced by businesses [11, 12], identified that companies had a variety of financial concerns about the cost of implementing practices for a sustainable business. Attitudes. Some businesses believe that their actions have a minimal impact on the environment [12], while others believe they have a moral responsibility to act [13]. Some firms have shown skepticism towards the implementation of this strategy as they do not see it as an opportunity for a competitive advantage. But other firms reported having a competitive advantage after implementing the measures [12]. Consumer Demand. Studies have found that businesses do not face pressure from customers, suppliers, or stakeholders to implement environmental practices. In the study Revell et al. [11], a study of 220 firms, two-thirds cited that pressure from consumers was considered insignificant and 78% said pressure from suppliers was ‘neutral’. Also, 74% do not feel pressured by business stakeholders.
2 Methodology The literature shows that there are a variety of research methodologies and instruments that help generate data and information related to this study. In this context, quantitative research method is defined as a multidisciplinary field that helps us understand numbers, statistics, experiments, etc. [14, 15]. According to Aliaga and Gunderson [16] the quantitative research method is the explanation of the phenomenon through the collection of numerical data which are then analyzed based on mathematical methods and in particular statistical methods. The realization of the research was designed in such a way as to facilitate the collection of information and at the same time to achieve satisfactory results that would help to draw the most accurate conclusions regarding the development and sustainable business and its implementation in Albanian companies. The questionnaire was requested to be completed by the administrators or managers of the companies (SME or large) operating in Tirana, and the way of interviewing was direct.
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Sample size of at least 30 and at most 500 is suitable for conducting most research [17]. According to Field [18] there are many rules regarding the volume of choice, but as a general rule 10–15 answers are needed for variables. 115 companies were selected to conduct the study, of which only 93 agreed to become part of it. The companies of this study belong to different fields such as, industry, trade, construction, transport, service, production, etc. and this selection was made to see if this concept was known in all these sectors and to what extent its knowledge reaches. The data collection process took about 3 weeks (January 22-February 12) and the data processing was made possible through the scientific method E-Views.
3 Data Analyses Of the total number of companies (93) surveyed, 60.2% (56 companies) belong to the category of large business and 39.8% of them (37 companies) belong to SMEs. In terms of operating time in the market, most of the companies surveyed, about 35.5% operate for a period of 6–10 years; 21.5% of a period of 11–15 years; 20.4% 16–20 years; 11.8% are 1–5 years old and 10.8% 21–26 years old. Regarding the orientation towards sustainable development 36% of companies think that this process is very important considering it as a necessary need, 37% think that the orientation towards sustainable development is necessary but not necessary giving a sufficient assessment. Regarding the costs of implementing sustainability, about 75% of companies answered that they constitute an investment, while 25% answered that these costs constitute more costs than investment. About 9.7% of companies think that having a stable business has a much higher cost than an unsustainable business, 58% think it has a high cost, 28.3% think it has the same cost and only 5% think that it has low cost. Factor Analysis Factor analysis, used in this study, studies the possible logical relationships between search variables, statistically significant relationships (correlations) of search variables, the importance of the model taken in the study and the problems from which it may “suffer”. Dependent variable is the degree of sustainable development implementation or simply sustainable development, which is defined as the percentage of implementation of the most profitable practices. What are some of the factors that most influence the implementation or not of sustainable development? This is the question that the built model has tried to answer. Some of the factors that mainly affect the implementation of development are: 1. 2. 3. 4. 5. 6.
Business category. Operating time in the market. Implementation cost. Barriers encountered during implementation. The benefits that companies have from the implementation. Knowledge of the concept of sustainable development.
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In the realized study it has been reached in the form of a log-log type model, which is otherwise called multiple regression (because there are more than two independent variables) and has the form: Log(SD) = β0 + β1 log(BC) + β2 log(MOT) + β3 log(IC) + β4 log(ChI) + β5 log(BI) + β6 log(KSD). SD = Sustainable development. BC = Business Category. MOP = Market operation time. IC = Implementation cost. ChI = Challenges encountered during implementation. BI = Benefits that companies have from implementation. KSD = Knowledge of the concept of sustainable development. From the descriptive analysis it was concluded that the main factors in the implementation of sustainable development are the time of operation in the market, the business category and the knowledge of the concept, which means that the newer the businesses the better informed and more are inclined towards sustainable development. To analyze the level of implementation of sustainable development depending on the cost of implementation, barriers encountered during implementation and the benefits that companies have from implementation, it is important to study the importance of the model through the Fisher test. Ho: β3 = β4 = β5 not important model. Ha: β3 = β4 = β5 important model. Table 1. Importance of the model Dependent Variable: LOG (SD) Variable
Coefficient
Std. Error
t-Statistic
Prob.
C
−4.155107
3.011694
−1.379658
0.1879
LOG (IC)
−0.831271
0.667652
−1.245066
0.2322
LOG (ChI)
−0.753340
0.756805
−1.301203
0.0637
2.102301
LOG (BI)
1.593340
0.757903
R-squared
0.739958
Mean dependent var
7.930775
0.0528
Adjusted R-squared
0.705285
S.D. dependent var
0.310176
S.E. of regression
0.168387
Akaike info criterion
−0.574088
Sum squared resid
0.425315
Schwarz criterion
−0.425692
Log likelihood
8.166789
Hannan-Quinn criter
−0.553626
F-statistic
21.34144
Durbin- Watson stat
1.100224
Prob (F-statistic)
0.000041
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From the above data we see that Fv = 21,341 > Fkr (5), so the value of Fisher is greater than the value of the critical Fisher which means that the hypothesis Ho falls down or Ha stands, so the model is globally important. Testing the Importance of Coefficients The importance of coefficients (variables) is based on Student statistics (tv). Ho: β3 = β4 = β5 = 0 non-significant coefficients. Ha: β3 = β4 = β5 = 0 significant coefficients. About β3: Because tv = −1.24 > t*(=−2) → Ho stand, which means that the coefficient is not significant. About β4: Because tv = −1.3 > t*(=−2) → Ho stand, which means that the coefficient is not significant. About β5: Becauset v = 2.1 > t*(=2) → Ho falls which means that the coefficient is important. Another very important problem during regression analysis is the verification of normal distribution. To prove such a thing we use two statistical indicators, S (skewness) = 0 and K (kurtosis) = 3, but in practice it is impossible for these values to be fixed and this is actually proven in the following table of normal distribution where the values of S and K are S = 0.457; K = 2.62. Ho: Ui ˜ N ( 0; σ 2 ) normal distribution. Ha: Ui = N ( 0; σ 2 ) not normal distribution. Ui is normal distribution. N is number of observations. σ 2 standard deviation. In this case we will analyze through statistics JB (Jarque-Bera), whose value must be greater than χ2 , and through the value of P. The condition for having normal waste distribution is that the value of P is greater than the value of the constant α = 0.05. Jarque-Bera shows us the deviation of the waste distribution from the values of S and K. JB = 0.735; P = 0.69 > α = (0.05), which means that Ho stands, so the model residues have normal distribution (Fig. 1). So, from the study and analysis so far, with the help of relevant statistics or tests, we have concluded that the model we have built is a globally important model, with significant coefficients and normal waste distribution. For the analysis to be complete, the problems that the model may display or the problems from which it “suffers” should also be studied. These problems are: multicollinearity, autocorrelation, heteroscedasticity.
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8
Series: Residuals Sample 1994 2011 Observations 18
7 6 5 4 3
Mean Median Maximum Minimum Std. Dev. Skewness Kurtosis
1.19e-15 -0.049498 0.318628 -0.298500 0.158172 0.457356 2.620059
Jarque-Bera Probability
0.735789 0.692190
2 1 0 -0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
Fig. 1. Normal distribution
Multicollinearity. Since in the above studies it turned out that the model is important and two of the coefficients are insignificant, multicollinearity is suspected but we cannot say anything for sure. For this from Table 1 we study the difference between R2 (coefficient of determinability) and R2 a (Adjusted R-squared). The value of R2 is approximately equal to 1 and in multiple regressions loses clarity therefore analysts have suggested the correction of this coefficient. From the table above we have: R2 = 0.739 and R2 a = 0,705. We see that there is a difference between these coefficients and we can say that it is suspected that the model suffers from multicollinearity, and if the model suffers from multicollinearity it means that, is a correlation between the variables. To determine exactly whether there is a correlation between them and the model suffers from multicollinearity, we construct correlation matrices between independent variables (implementation cost (IC), challenges encountered during implementation (ChI), benefits that companies have from implementation (BI)). Correlation matrices has values r for IC-ChI = 0.989591, r for IC-BI = 0.898519 and r for BI-ChI = 0.816423. So all three values are insignificant and we can say that there is no correlation between the variables and the model does not suffer from multicollinearity. In addition to the study of multicollinearity through the correlation matrix, we can also judge through the study of VIF (Variance Inflation Factors). From the data provided, the VIF values are less than 10 for the four variables (along with the constant C), which means that the model does not suffer from multicollinearity. Autocorrelation. Darbin Watson (DW) test is used to quickly detect if such a problem exists. Based on the data provided we cannot determine whether the model suffers from autocorrelation because the value of Durbin Watson is 1.1 and is included in the sector for which we cannot judge. For this reason, to see if the initial model suffers from autocorrelation, we add another variable ar (1) and continue testing through the program judging again based on DW statistics. Therefore, we already have the model in this form:
Challenges of Albanian Companies for Sustainable Development
Log(SD) = β0 + β1 log(BC) + β2 log(MOT) + β3 log(IC) + β4 log(ChI) + β5 log(BI) + β6 log(KSD) + ar
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(1)
From the data processing, it results that already the value of DW has changed and is 2.04, so a value which allows us to say with certainty that the model does not suffer from autocorrelation. Heteroscedasticity is the situation in which by changing one of the variables, the corresponding variation changes. To analyze this, we use the model White and model BPG (Breusch-Pagan-Godfrey). According to model White: U2 = −16,42 − 0.919log(IC) + 0.254log(IC)2 − 0.329log(IC)*log(ChI)3.307log(ChI) + 0.223 log (ChI)2 − 0.390 log(ChI)*log(BI) − 2.988 log(BI) + 0.211log (BI)2 . Ho: The White model is not important, which means that the model does not suffer from heteroscedasticity. Ha: The important White model, which means that the model suffers from heteroscedasticity (Table 2). Table 2. Heteroscedasticity white test F-statistic
2.033482 Prob. F(4,13)
Obs*R-squared
6.927757 Prob. Chi-Square (4) 0.1398
0.1488
Scaled explained SS 3.897005 Prob. Chi-Square (4) 0.4201
F-statistic = 2.033 < Fkr, so Ho stands, White model not important i.e. the model does not suffer from heteroscedasticity. According to BPG model U2 = 1.07 + 0.27log(niv) – 0.3 log(tr). Ho: BPG model not important, which means that the model does not suffer from heteroscedasticity. Ha: Important BPG model, which means that the model suffers from heteroscedasticity. Fv = 0.06 < Fkr → Ho stands, BPG model unimportant, meaning that the model does not suffer from heteroscedasticity. So, the constructed model is a multiple, globally important regression otherwise called the homoscedastic model which does not display any of the possible problems like heteroscedasticity, multicollinearity or autocorrelation.
4 Conclusion Regarding the concept of sustainable development, most companies have knowledge of this concept, and most of them are interested and find it important to orient towards this concept. However, Albania is still in the early stages of the journey towards implementing sustainable business practices.
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78% of companies have taken initiatives towards the implementation of sustainability, and this is a good thing as the interest towards this concept has grown and more and more efforts are being made to implement it. This will have a positive impact not only on improving the success of the company in the future but also on the economic, social and environmental aspects of our country. From the implementation of sustainable development companies benefit from improved reputation, lower costs, improved brand, will be more competitive in the market, there will be increased customer demand and opportunities to enter new markets. Regarding the process of implementation of this concept, it is a bit “complicated” and there are barriers among which we will mention mainly: high cost of implementation, lack of incentives by the government and lack of interest from the consumer. During the study of the significance of the constructed model, through Fisher statistics, the model turned out to be globally important, which means that it is further study and the coefficients of the variables obtained in the study proved to be important. From this study business category, operating time in the market, implementation cost, barriers encountered during implementation, the benefits that companies have from the implementation and knowledge of the concept of sustainable development, are important factors that influence in sustainable development implementation. During the waste distribution study, the model resulted in normal distribution and this means that we are dealing with a homoscedastic model. Regarding the problems that a model may exhibit, such as heteroscedasticity, multicollinearity and autoregression, in our model these problems do not exist.
References 1. WCED, Our common future, 1987 Oxford, Oxford University Press 2. Porritt, J.: Sustainable development. New Econ. 10(1), 28–33 (2003). https://doi.org/10.1111/ 1468-0041.00285 3. Stabler, M.J.: Tourism sustainability: principles to practice. J. Travel Res. 37(1), 86 (1998). https://doi.org/10.1177/004728759803700150 4. Shyle, I.: Awareness of individuals and businesses in Albania for sustainable development. European Journal of Multidisciplinary Studies 3(1), 46–54 (2018) 5. Tonelli, F., Evans, S., Taticchi, P.: Industrial sustainability: challenges, perspectives, actions. Int. J. Bus. Innov. Res. 7(2), 143–163 (2013) 6. Sartal, A., Martinez-Senra, A.I., Cruz-Machado, V.: Are all lean principles equally ecofriendly? a panel data study. J. Clean. Prod. 177, 362–370 (2018) 7. Oláh, J., Aburumman, N., Popp, J., Khan, M.A., Haddad, H., Kitukutha. N.: Impact of Industry 4.0 on Environmental Sustainability. Sustainability 12(11), 4674 (2020). https://doi.org/10. 3390/su12114674 8. Stock, T., Seliger, G.: Opportunities of sustainable manufacturing in industry 4.0. Procedia CIRP 40. In: Proceedings of the 13th Global Conference on Sustainable ManufacturingDecoupling Growth from Resource Use, Berlin, Germany, 16–18 September 2011, pp. 536– 541 9. Shaper, M.: Introduction: the essence of ecopreneurship. Greener Management International: Theme Issue: Environmental Entrepreneurship Summer, pp. 26–30 (2002) 10. Revell, A., Blackburn, R.: The business case for sustainability? an examination of small firms in the UK’s construction and restaurant. Bus. Strategy Environ. 16(6), 404–20 (2007)
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11. Revell, A., Stokes, D., Chen, H.: Small businesses and the environment: turning over a new leaf? Bus. Strat. Environ. 19(5), 273–288 (2010) 12. Taylor, N., Barker, K., Simpson, M.: Achieving ‘Sustainable Business’: A Study of Perceptions of Environmental Best Practice by SMEs in South Yorkshire. Environ. Plann. C: Government Policy. 21(1), 89–105 (2003). https://doi.org/10.1068/c0219 13. Jenkins, H.: Small business champions for corporate social responsibility. J. Bus. Ethics 67, 241–256 (2006). https://doi.org/10.1007/s10551-006-9182-6McWilliams,A.;Parhankan gas,A.;Coupet,J 14. Janesick, V.J.: The dance of qualitative research design: metaphor, methodolatry, and meaning. In: Denzin, N.K., Lincoln, Y.S. Strategies of Qualitative Inquiry (1998) 15. Corbetta, P.: Social Research Theory, Methods and Techniques. SAGE Publications, London (2003) 16. Aliaga, M., Gunderson, B.: Interactive Statistics, 2nd edn. Prentice Hall, Upper Saddle River, NJ (2003) 17. Sekaran, U.: Research Methods for Business: A Skill Building Approach, 4th edn. John Wiley and Sons, Hoboken, NJ (2003) 18. Field, A.P.: Is the meta-analysis of correlation coefficients accurate when population correlations vary? Psychol. Methods 10(4), 444–467 (2005). https://doi.org/10.1037/1082-989X. 10.4.444
Analysis of Innovation Activities in Georgia as a Major Factor in Application of the Industry 4.0 Concept Raul Turmanidze1(B) , Predrag Daši´c2 , and Giorgi Popkhadze1 1 Faculty of Transportation and Mechanical Engineering, Georgian Technical University
(GTU), Tbilisi, Georgia 2 Academy of Professional Studies Šumadija – Department in Trstenik, 37240 Trstenik, Serbia
Abstract. One of the main requirements for the successful implementation of the Industry 4.0 concept in a country and/or region is certainly its digital infrastructure, and the main driving factors are certainly innovation and educational and training activities. The paper presents the trend analysis of innovation activities and global innovation index (GII) in Georgia for the period 2011–2020. For GII index values for CAGR (compound annual growth rate) and AAGR (average annual growth rate) are −0.0353 and 1.39, respectively. Keywords: Industry 4.0 · Innovation · Global Innovation Index (GII) · Innovation Capacity Index (ICI) · Global Competitiveness Index (GCI)
1 Introduction New Industry 4.0 or 4IR (fourth industrial revolution) is a new generation of digitized factories that are based on a combination of cyber-physical systems (CPS), robots and digital and Internet (IIoT, IoP, IoS, IoT and etc.) technologies [1–5]. The requirements for the successful implementation of the Industry 4.0 concept of a country and/or region are certainly: digital infrastructure, application of new technologies and education and training of personnel for a new form of production. The trend of development and application of digital infrastructure in Georgia is presented in papers [6, 7]. The main drivers for the successful implementation of Industry 4.0 concept are certainly innovation and educational and training activities of a country and/or region. Innovation is the practical application of new and improved ideas, resulting in the introduction of new products, materials, services, processes, methods, technologies or improvement in offering product, services, production process, etc. Basic terms in the field of “innovation management” are defined by the international standard ISO 56000:2020 [8]. Innovation activities include the stages of creating innovation from the idea to the analysis, design and production (realization) of a new product or service and the introduction of a new method or production process. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 270–277, 2021. https://doi.org/10.1007/978-3-030-75275-0_31
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Several indices have been introduced to measure the performance and capacity of innovation, such as: • • • • •
Bloomberg Innovation Index (BII), Global Innovation Index (GII) [9–11], Innovation Capacity Index (ICI) [12, 13], International Innovation Index (III), Management Innovation Index (MII) and etc.
Science reviews of measuring innovation are presented in the papers [14, 15] and for Georgia country [16, 17]. Values for the GII index for different years and countries have been analysed for: Brazil in the paper [18], Kazakhstan in the papers [19, 20], Poland and Bulgaria in the paper [21], Russia in the papers [22–24], countries of the former USSR in the paper [25], Serbia in the paper [26] and Saudi Arabia in the paper [27]. The ranking scores on the GII using the artificial neural network was presented in the paper [28]. Educational and training activities include the implementation of modern educational systems and the application of methods and technologies of classical (traditional) and new online (distance) learning [29], with the possibility of practical application directly in industrial plants. Perspective application of international literature on the development of state and private higher education in Georgia is presented in the paper [30]. This paper presents the trend analysis of only innovation activities in Georgia for the period 2011–2020.
2 Data and Methods Data on values of Global Innovation Index (GII) for Georgia country has been retrieved from GIR editions for period 2011–2020 [9–11], with a certain calculation from the part of the authors. Data on values of Innovation Capacity Index (ICI) for Georgia and neighbouring countries have been retrieved from ICR editions for period 2009–2010 and 2010–2011 [12, 13]. Data on values of Global Competitiveness Index (GCI) for Georgia and neighbouring countries has been retrieved from GCR editions for period 2010 and 2019 [30, 31]. For the trend analysis, we used the following parameters: annual growth rate (AGR), average annual growth rate (AAGR), compound annual growth rate (CAGR) and cumulative growth index (CGI), described in the papers [33–36].
3 Results and Discusions The Global Innovation Index (GII) is an indicator which annual ranking of countries by their capacity and success in innovation and innovative activities [9–11, 26], published by Cornell University, INSEAD (in French: Institut Européen d’Administration des Affaires – European Institute of Business Administration) and the WIPO (World Intellectual Property Organization). The GII was calculated based on a large number of indicators,
272
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5.51
36.98
7.62 3.67
34.39
33.86
33.83
34.53
0.09 -2.03
1.92
35.05
1.57
-2.90
34.0
0
-4
31.78
32.0
4
35.56 34.30
36.0
Annual growth ratio (AGR) [%]
8
38.0
31.87
Global Innovation Index (GII)
grouped into two sub-indices: Innovation Input Sub-Index (IISI) and Innovation Output Sub-Index (IOSI) [9–11, 26, 37]. The GII 2020 edition [11] ranks 131 countries based on 80 indicators, with values of GII index which are found in intervals from 66.08 (Switzerland) to 13.56 (Yemen). Trend analysis for Global Innovation Index (GII) with annual growth rate (AGR) for Georgia country for the period 2011–2020 is shown on Fig. 1. The highest growth/decrease of annual growth rate (AGR) was by −14.06 in 2020 year.
-8
-12 -14.06 30.0
-16 2011
2012
2013
2014
2015
2016
Global Innovation Index (GII)
2017
2018
2019
2020
Annual growth ratio (AGR) Year
Fig. 1. Trend analysis of Global Innovation Index (GII) with annual growth rate (AGR) for Georgia for the period 20011–2020
The Georgia country was in quartile Q2 and Q3 according to the GII index, for the observed period 2009–2020. The data about global innovation index (GII) for Georgia for the period 2011–2020 changed in intervals from 31.78 (2020) to 36.98 (2019), with arithmetic mean (AM) of 34.2150, geometric mean (GM) of 34.1827, harmonic mean (HM) of 34.1503 and median (Med) of 34.345. The standard deviation (SD) is 1.5632, variance (Var) is 2.4435, coefficient of variation (CoV) is 4.5686, skewness (Skew) is −0.1179 and kurtosis (Kurt) is 0.3271. Due to a large increase in the value of the GII index in 2012 (AGR = 7.62 [%]) and large decrease in the value of the GII index in 2020 (AGR = −14.06 [%]), the GII index is low, decreased by −0.28 [%] (CGI = 99.72 [%], CAGR = −0.0353 [%] and AAGR = 1.39) in 2020 compared to 2011. Trend analysis for Innovation Input Sub-Index (IISI) with annual growth rate (AGR) for Georgia country for the period 2011–2020 is shown on Fig. 2. The highest growth/decrease of annual growth rate (AGR) was by −8.92 in 2020.
43.89
44.44
0
-5
38.54
41.10
-1.96
41.02
-1.25
41.62
44.0
41.84
-0.19
5
2.78
1.80
42.16
48.0
40.0
10
8.44 5.41
273 Annual growth ratio (AGR) [%]
8.20
48.19
52.0
41.70
Global Innovation Index (GII)
Analysis of Innovation Activities in Georgia as a Major Factor
-8.92
-10
-15
36.0 2011
2012
2013
2014
2015
2016
2017
Innovation Input Sub-Index (IISI)
2018
2019
2020
Annual growth ratio (AGR)Year
0
0.43
-0.37
24.0
25.76
5
25.65
3.49
26.61
26.71
25.81
26.80
28.0
10
27.95
29.49
10.04
6.35
-5
-3.61 -5.22 -7.66
Annual growth ratio (AGR) [%]
15
32.0
25.2
Global Innovation Index (GII)
Fig. 2. Trend analysis of Innovation Input Sub-Index (IISI) with annual growth rate (AGR) for Georgia for the period 2011–2020.
19.66
-10
20.0
-15 -20
-23.68 16.0
-25 2011
2012
2013
2014
2015
2016
Innovation Output Sub-Index (IOSI)
2017
2018
2019
2020
Annual growth ratio (AGR) Year
Fig. 3. Trend analysis of Innovation Input Sub-Index (IISI) with annual growth rate (AGR) for Georgia for the period 2011–2020
31.87
33.00
29.17
35.85
34.11
Armenia
Azerbaijan
Russia
Turkey
65/125
56/125
88/125
69/125
73/125
34.90
35.63
27.23
32.64
31.78
51/131
47/131
82/131
61/131
63/131
50.8
52.8
47.3
–
55.1
59/131
49/131
74/131
–
42/131
Rank
50.2
52.8
53.8
–
55.0
Score
2010–2011
2009–2010 Score
Score
Rank
2020
Score
2011
Rank
Innovation capacity index (ICI)
Global innovation index (GII)
Georgia
Country
62/130
56/130
50/130
–
44/130
Rank
4.28
4.21
4.31
3.89
3.95
Score
2011
59/142
66/142
55/142
92/142
88/142
Rank
62.1
66.7
62.7
61.3
60.9
Score
2019
Global competitiveness index (GCI)
Table 1. Typical international rating of innovation development of Georgia and neighbouring countries
61/141
43/141
58/141
69/141
74/141
Rank
274 R. Turmanidze et al.
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Trend analysis for Innovation Input Sub-Index (IISI) with annual growth rate (AGR) for Georgia country for the period 2011–2020 is shown on Fig. 3. The highest growth/decrease of annual growth rate (AGR) was by -23.68 in 2020. Table 1 shows a typical international rating of innovation development of Georgia and neighbouring countries. Based on the GII index in 2011 and 2020, the neighbouring countries Russia and Turkey have a better rating than Georgia. Based on the ICI index in 2009–2010 and 2010–2011, Georgia has the best rating compared to neighbouring countries. Based on the GCI index in 2011 and 2019, Georgia has the worst rating compared to the neighbouring countries.
4 Conclusion The data about GII index for Georgia country for the period 2011–2020 changed in intervals from 31.78–36.98. The indicators of central tendency of GII index of Georgia for the period 2011–2020 are: AM = 34.2150, GM = 34.1827, HM = 34.1503 and Med = 34.345. Due to a large increase in the value of the GII index in 2012 (AGR = 7.62 [%]) and large decrease in the value of the GII index in 2020 (AGR = −14.06 [%]), the GII index is low, decreased by −0.28 [%] (CGI = 99.72 [%], CAGR = [%] and AAGR = 1.39) in 2020 compared to 2011. COVID-19 (Coronavirus Disease of 2019) most likely affected the largest decrease in the GII index for Georgia country for the period 2011–2020 (AGR = −14.06 [%]). Acknowledgment. This paper was supported by Shota Rustaveli National Science Foundation (SRNSF) [PHDF-19–2224, Improving the efficiency of mechatronic systems in order to ensure the reform of “Industry-4.0”].
References 1. Karabegovi´c, I., Kovaˇcevi´c, A., Banjanovi´c-Mehmedovi´c, L., Daši´c, P. (eds.): Handbook of research on integrating Industry 4.0 in business and manufacturing. IGI Global, Hershey, Pennsylvania, USA, 661 pp. (2020). https://doi.org/10.4018/978-1-7998-2725-2 2. Daši´c, P.: Scientific and technological trends: Selected scientific-professional papers. SaTCIP Publisher Ltd., Vrnjaˇcka Banja, Serbia, 305 pp. (2020). (in Serbian) 3. Oztemel, E., Gursev, S.: Literature review of Industry 4.0 and related technologies. J. Intell. Manuf. 31, 127–182 (2020). https://doi.org/10.1007/s10845-018-1433-8 4. Turmanidze, R., Daši´c, P., Popkhadze, G.: Industry 4.0: New manufacturing philosophy. In: Proceedings of the 18th International Conference Research and Development in Mechanical Industry (RaDMI-2018), SaTCIP Publisher Ltd., Vrnjaˇcka Banja, Serbia, pp. 63–74 (2018) 5. Turmanidze, R., Daši´c, P., Popkhadze, G., Borodavko, B.: Survey of the role of modern requirement mechatronic systems in the process of implementation Industry-4.0 reforms. In: Proceedings of the 8th International Conference Economics and Management-Based on New Technologies (EMoNT-2018), SaTCIP Publisher Ltd., Vrnjaˇcka Banja, Serbia, pp. 15–28 (2018)
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6. Turmanidze, R., Daši´c, P., Popxadze, G.: Statistical analysis of e-government development index (EGDI) of Georgia. Lecture Notes in Networks and Systems (LNNS) 128, 930–938 (2020). https://doi.org/10.1007/978-3-030-46817-0_105 7. Turmanidze, R., Daši´c, P., Popkhadze, G.: Digital infrastructure in Georgia as a condition for successful application Industry 4.0. Int. Sci. J. Ind. 4.0, 5(1), 3–6 (2020) 8. ISO 56000:2020 Innovation management -- Fundamentals and vocabulary. International Organization for Standardizations (ISO), Geneva, Switzerland, 37 pp. (2018) 9. Dutta, S. (ed.): The Global Innovation Index 2011: Accelerating growth and development. World Intellectual Property Organization (WIPO), Geneva, Switzerland & Institut Européen d’Administration des Affaires (INSEAD), Fontainebleau, France, 358 pp. (2011) 10. Dutta, S., Lanvin, B., Wunsch-Vincent, S. (eds.) The Global Innovation Index 2019: Creating healthy lives - The future of medical innovation. World Intellectual Property Organization (WIPO), Geneva, Switzerland, 399 pp. (2019) 11. Dutta, S.; Lanvin, B., Wunsch-Vincent, S. (eds.): The Global Innovation Index 2020: Who will finance innovation? World Intellectual Property Organization (WIPO), Geneva, Switzerland, 399 pp. (2020) 12. López-Claros, A. (ed.): The innovation for development report 2010–2011: Innovation as a driver of productivity and economic growth. Palgrave Macmillan Ltd., Basingstoke, United Kingdom. 335 pp. (2012). https://doi.org/10.1057/9780230299269 13. Hayat, E., Liyanage, C., Haigh, R., Amaratunga, D.: Development of research and innovation capacity index of HEIs on disaster resilience related studies. Procedia Eng. 212, 1249–1256 (2018). https://doi.org/10.1016/j.proeng.2018.01.161 14. Saunila, M., Pekkola, S., Ukko, J.: The relationship between innovation capability and performance: the moderating effect of measurement. Int. J. Prod. Performance Manage. 63(2), 234–249 (2014). https://doi.org/10.1108/IJPPM-04-2013-0065 15. Ter Haar, P.: Measuring innovation: a state of the science review of existing approaches. Intangible Capital 14(3), 409–428 (2018). https://doi.org/10.3926/ic.1254 16. Kurdadze, M.: Innovation, high technology sectors, higher education and human capital: education system reform in Georgia. Transition Stud. Rev. 17(2), 464–470 (2010). https:// doi.org/10.1007/s11300-010-0151-5 17. Youtie, J., Shapira, P., Roper, S.: Exploring links between innovation and profitability in Georgia manufacturers. Econ. Dev. Q. 32(4), 271–287 (2018). https://doi.org/10.1177/089 1242418786430 18. Morgado, E.M.: Brazil in the global innovation index 2012: Deepening the understanding of the results. Sistemas, Cibernética e Informática - Systemics, Cybernetics and Informatics (SC&I), 10(2), 33–37 (2013). (in Portuguese) 19. Issayeva, G.K., Zhussipova, E.Y., Kuralbayeva, A.S., Beisenova, M.U., Maulenkulova, G.E., Zhakipbekova, D.S.: Convergent technologies in science and innovations in Kazakhstan. Bus. Soc. Rev. 125(4), 411–424 (2020). https://doi.org/10.1111/basr.12215 20. Stavbunik, Y., Pelucha, M.: The innovation system of Kazakhstan in the context of the global innovation index. Innov. J. Public Sector Innov. J. (TIJ) 24(1), 1–24 (2019) 21. Jankowska, B., Matysek-J¸edrych, A., Mroczek-Dabrowska, K.: Efficiency of national innovation systems – Poland and Bulgaria in the context of the global innovation index. Comparative Econ. Res. 20(3), 77–94 (2017) 22. Davidson, N., Mariev, O., Pushkarev, A.: The impact of externalities on the innovation activity of Russian firms. Foresight STI Governance 12(3), 62–72 (2018) 23. Oveshnikova, L., Lebedinskaya, O., Timofeev, A., Mikheykina, L., Sibirskaya, E., Lula, P.: Studying the sector of the Russian high-tech innovations on the basis of the global innovation index INSEAD. Advances in Intelligent Systems and Computing (AISC) 726, 87–96 (2019)
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Dynamic Simulation of Worm Gears Using CAD Applications Alina Bianca Pop1 and Aurel Mihail T, ît, u2,3(B) 1 Technical University of Cluj-Napoca, 430083 Baia Mare, Romania 2 “Lucian Blaga” University of Sibiu, 10 Victoriei Street, 550024 Sibiu, Romania
[email protected] 3 The Academy of Romanian Scientists, 050085 Bucharest, Romania
Abstract. The new processes by plastic deformation of the gears eliminate some of the shortcomings of the old methods of their manufacture, at the same time reducing the production costs and the time of realization of the mass production. To carry out this research, the AutoDesk INVENTOR PROFESSIONAL application was chosen. A worm gear was designed, after which the calculations for the worm and worm wheel were performed. Of particular importance for gear, mechanisms are the research of dynamic loads. The use of modern calculation methods, which have wide possibilities for rapid optimization of prototypes, ensures the minimization or sometimes even exclusion of the execution of experimental samples. This possibility arose with the development of Computer-integrated manufacturing. In this context, all the steps from the idea to the final product are performed integrated on the computer. It is also important to reduce dynamic loads with different methods. By simulating the behavior of a machine or other engine-driven assemblies, one can better understand how they will operate without the need to make a real prototype. Dynamic Simulation in Autodesk Inventor Professional can be used to analyze the dynamic operating conditions of a project in a complete operating cycle. Dynamic Simulation provides analysis tools that allow the evaluation of product performance in a 3D environment. Keywords: Worm gear · Worm · Worm wheel · Dynamic simulation · CAD application
1 Introduction Among current mechanical transmissions, geared transmissions have the widest use, ensuring compact and reliable constructions for the entire power range of the machines (from a few watts to tens of thousands of kilowatts). Geared transmissions include: gearboxes, gearboxes, drives, complex transmissions. The simplest transmission (mechanism) with gears consists of gears in gear and is called gear [1, 2]. The worm gear consists of two gear with inclined teeth, so that the angle between the axles is equal to the difference between the angle of the drive wheel and the angle of the driven wheel [3, 4]. δ = β1 − β2 © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 278–285, 2021. https://doi.org/10.1007/978-3-030-75275-0_32
(1)
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As a result, we can write γ = 90° —β1, and the magnitude of the angle between the axes will be given by: δ = 90◦ − (γ + β2)
(2)
2 Processing of Worm and Worm Gear The worm used in the worm gear can be processed; by turning, milling and grinding [5, 6]. Regardless of its shape (evolutionary, archimedical or convoluted), it can be processed by turning on ordinary lathes, using knives with rectilinear edges, taking into account the way of generating the respective surface [7]. Disc milling can be applied to any type of screw, the profile of the cutter must have the shape of the profile in the normal section on the screw propeller [8]. In the case of convoluted snail the profile is rectilinear [9]. The finishing operation of the snails is required due to the fact that they are always subjected to a heat treatment [10, 11]. The finishing operation can be done by sanding or grinding. Grinding is performed, with abrasive powder and oil, on the lathe, with the help of wooden pliers. This operation cleans the thread surface of the worm resulting from hardening, but cannot ensure an improvement of the thread profile [12, 13]. Worm grinding involves machines corresponding to the type of snail. Archimedean and convoluted snails are ground with a disc abrasive stone with the axis normally arranged on the worm propeller or with large diameter annular conical stones. Small worm gear can be machined on the universal milling machine, with a milling cutter - disc - module, the division being performed with the divider head, and the feed, in the radial direction.In order to obtain a more correct tooth shape, the diameter of the disc cutter must be as close as possible to the size of the worm diameter. Often the snail is built to the diameter of the available disc mill [14, 15]. A substantial improvement of the worm gear is obtained using a milling cutter - worm-module corresponding to the worm, with the help of which the worm wheel is finished, on the universal milling machine, the worm wheel rotating freely between the tips. For series production, worm gear are machined on milling machines with screw milling cutter, by three methods: radial, tangential and combined.It should be noted that the worm milling machine used in the processing of worm gear must correspond to the type of worm (archimedic, convoluted or evolutionary) with which the worm wheel will engage [16, 17]. An economical method of processing worm gear on gear milling machines, in the case of single or a small number of gear, for which the manufacture of a worm cutter would not be economical, is to use instead of the worm cutter properly mounted on a mandrel. The finishing of the worm gear is usually done on the same machines on which their teeth were processed. The tools used are special screw milling cutters, with or without adjustable calibration teeth. Snake-like snails are also used for fine tooth scraping [18]. In general, however, the finishing operation presents difficulties in that the tool with which the finishing is done must have the smallest possible deviations from the shape and dimensions of the worm with which it will engage the worm wheel and be arranged at the same distance and in the same position as in the aggregate in which the worm gear will work [19, 20].
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3 Dynamic Simulation of Worm Gears Using CAD Applications AutoDesk INVENTOR PROFESSIONAL was chosen to conduct this research. Using the information provided by https://www.girard-transmissions.com, the 3D model of a worm gearbox in the form of a stp file was imported into AutoDesk INVENTOR. Using the Accelerator Design module of the INVENTOR application, the necessary steps to make a worm gear and calculate its power are:
Fig. 1. Worm and worm wheel parameters
Fig. 2. The results of the worm and worm wheel calculations
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• gear geometry design (worm and worm wheel design); • verification calculation (verification of the resulting data); • choosing worm and worm wheel material. Starting from the worm and worm wheel parameters shown in Fig. 1, the worm gear was designed. Worm and worm wheel calculations were performed. The results obtained are presented below in Fig. 2 [18].
4 Dynamic Simulation Of particular importance for gear mechanisms is the research of dynamic loads. The use of modern calculation methods, which have wide possibilities for rapid optimization of prototypes, ensures the minimization or sometimes even exclusion of the execution of experimental samples. This possibility arose with the development of Computerized Production Integration (CIM). In the context of this path, all the steps from the idea to the final product are performed integrated on the computer. At first, using computer-aided design (CAD) programs, the mechanisms are designed, and then precise 3D virtual models are used for numerical calculations (CAE), production processes (CAM), control (CAQ), etc.It is also important to reduce dynamic loads by different methods. The methods of static and dynamic balancing of the elements with an advanced dynamic action more frequently used, the constructive-technological methods of reducing the dynamic loads, etc. can be mentioned.By simulating the behavior of a mechanism or other engine-driven assemblies, one can better understand how they will operate without the need to make a real prototype. Dynamic Simulation in Autodesk Inventor Professional can be used to analyze the dynamic operating conditions of a project in a complete operating cycle.In the case of many machines, the performance of the functions depends on the movement and synchronization of their components. As a result, understanding the movement of components is very important in the design process. In the past, this was expensive and time consuming, requiring prototype testing and special analysis. Dynamic Simulation provides analysis tools that allow the evaluation of product performance in a 3D environment. Dynamic Simulation provides animation, kinematic study of trajectories and positions, and dynamic analysis to verify synchronization and determine forces. Through the improvements made to the virtual prototype, Dynamic Simulation accelerates the design process and allows obtaining quality products. Dynamic simulation can be used to add information about the movement of components in a pre-made assembly. 4.1 Working Steps for Dynamic Simulation The working steps for Dynamic Simulation are presented below. Defining kinematic torques: Identifying the places where the components move relative to each other and choosing the type of torque from a set of available torques (translation, rotation, rolling, etc.). Defining the environment: Adding information about gravitational force, friction, damping, external forces and others.
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Running the simulation: Tracking the movement of the model, setting the duration of the animation and the number of repetitions, etc. Analysis of results: Generation of simulation information, including positions, speeds and accelerations, reactions, forces and moments. 4.2 Dynamic Loads for Resistance Calculation Dynamic Simulation and Finite Element Analysis (FEA) are complementary and work well together in Autodesk Inventor. The dynamic loads applied to a component are calculated by the Dynamic Simulation and automatically transferred to the Finite Element Analysis module for the calculation of stresses and strains. The analyzed component is in dynamic equilibrium throughout the dynamic simulation. Finite Element Analysis is performed at a certain point in time without taking into account the time variation of the loads. The steps for performing such an analysis are: • Dynamic Simulation calculates the reactions in the joints and the inertia forces acting on the studied component; • The loads determined in the previous step are transferred at the time considered to the analyzed component. The loads consist of reaction and inertia forces and the component is in dynamic equilibrium; • The Finite Element Analysis module calculates the deformations and stresses considering the selected component in static equilibrium.
5 Dynamic Simulation of Worm Gear Using the Autodesk Inventor Application Using the Autodesk Inventor application we have the possibility to perform the dynamic simulation of the worm gear. Thus, using the geometric parameters of the gear, as specified in the Girard-Transmission catalog, we can perform dynamic simulation of certain
Fig. 3. Applying constraints on gearbox parts
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parameters, such as: speed, acceleration, forces and moments that occur during operation.In order to be able to perform this simulation, first of all constraints must be made between the gearbox components. Axial and radial constraints were applied to the two input shafts, and for the gear a rotation constraint with worm-worm gear using the worm step to be able to achieve the transmission ratio (Fig. 3).
Fig. 4. Speed values on the input shaft
This study addressed the issue of dynamic simulation in terms of the influence of the transmission ratio on a variable speed at the input shaft. Figure 4 shows the introduction of different speeds on the input shaft at different time intervals. It can also be seen that the acceleration is related to these variations in speed. After entering these values, and using the configurations of the previously introduced torques, we perform the simulation
Fig. 5. Graphical representation of speeds on the input shaft (red curve) and the output shaft (blue curve). The worm pitch is 14 mm
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of the gear operation following both the dynamic movement of the 3D models and the generation of curves for the input shaft and the output shaft (Fig. 5). Figure 4 shows the change in speed on the output shaft depending on the variation of the speed on the input shaft. But by modifying the pich of the worm, we obtain in a very short time the values of these speeds (Fig. 6).
Fig. 6. Graphical representation of the speeds on the input shaft (red curve) respectively the output shaft (blue curve). The worm pitch is 10 mm
6 Conclusions Using Dynamic Simulation as an integral part of the development process, designers can analyze the performance of the designed product and make the necessary changes to improve it. The advantage of Dynamic Simulation is that it helps designers understand the behavior of a product and quickly analyze different variants and scenarios. Dynamic simulation reduces the need for expensive physical prototypes. Using virtual prototypes, it provides data on product behavior from the earliest stages of design. It is much easier to modify the virtual model than the physical prototype to get the desired result.
References 1. Pu, J., Wang, X., Wu, P., San, H., Chen, M.: Modeling and dynamic simulation of TI worm drive based on gear trax. In: 2019 IEEE 8th Data Driven Control and Learning Systems Conference (DDCLS), Dali, China, pp. 1355–1359 (2019) 2. Wang, S., Wang, S., Wang, J., et al.: Temperature field simulation and experimental study of anti-backlash single-roller enveloping hourglass worm gear. Chin. J. Mech. Eng. 33, 59 (2020) 3. Brown, C., McPhee, J.: Predictive forward dynamic simulation of manual wheelchair propulsion on a rolling dynamometer. ASME. J. Biomech. Eng. 142(7) (2020)
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4. Ankush, R.D., Darade, D.: Design and analysis of Worm pair used in Self-locking system with development of Manual Clutch (2014) 5. Boant˘a, C.I., Bolo¸s, V.: The mathematical model of generating kinematic for the worm face gear with modified. Procedia Technol. 1(12), 442–447 (2014) 6. Samsher, F.A., Kolhe, P.: Review paper on analysis of worm gear. Int. J. Recent Res. Civil Mech. Eng. (IJRRCME) 2(1), 54–58 (2011) 7. Magyar, B., Sauer, B.: Calculation of the efficiency of worm gear drives. International Gear Conference, Lyon, Elsevier Science, DOI 10(1533/9781782421955), 15 (2014) 8. Nenad, P., Branko, K., Zvonimir, M.I.: Determining an allowable wear of worm wheels, ISSN 1333–1124, eISSN 1849–1391, (2017). https://doi.org/10.21278/TOF.41205 9. Jbily, D., Guingand, M., de Vaujany, J.P.: A wear model for worm gear. J. Mech. Eng. Sci. (2015). https://doi.org/10.1177/0954406215606747 10. Zafar, A., Umida, N., Shakhnoza, K.: Modeling dynamic operation of mechanisms in Autodesk Inventor Professional 11. In: 2019 International Conference on Information Science and Communications Technologies (ICISCT), Tashkent, Uzbekistan, pp. 1–3 (2019) 11. Yakubov, M.S., Kiriadi, A.S.: Designing 3D models of scientific and technical developments. Reports of a scientific and practical conference, pp. 173–174 (2014) 12. Lee, J., Ware, B.: Three-dimensional graphics and animation, Williams, p. 640 (2002) 13. Afsari Kashani, S.: Optimal design and analysis of a novel reluctance axial flux magnetic gear. Scientia Iranica (2020). https://doi.org/10.24200/sci.2020.54093.3585 14. Deng, X., Wang, S., Qian, L., Liu, Y.: Simulation and experimental study of influences of shape of roller on the lubrication performance of precision speed reducer. Eng. Appl. Comput. Fluid Mech. 14(1), 1156–1172 (2020) 15. Paschold, C., Sedlmair, M., Lohner, T., et al.: Efficiency and heat balance calculation of worm gears. Forsch Ingenieurwes 84, 115–125 (2020) 16. Mautner, E.M., Sigmund, W., Stemplinger, J.P., Stahl, K.: Efficiency of worm gearboxes. Proc. Inst. Mech. Eng. Part C: J. Mech. Eng. Sci. 230(16), 2952–2956 (2016) 17. Tuan, N.K., Thao, T.T.P., Cam, N.T.H., Hung, L.X., Pi, V.N.: Optimum calculation of partial transmission ratios of mechanical driven systems using a V-belt and a three-step bevel helical gearbox. In: Fujita, H., et al. (eds.) ICERA 2018, LNNS, vol. 63, pp. 469–476 (2019) 18. T, ît, u, A.M., Pop, A.B.: Aspects regarding the modelling of geometric and strength calculations of worm gears using CAD applications. In: Gheorghe, G. (eds.) Proceedings of the International Conference of Mechatronics and Cyber- MixMechatronics - 2020. ICOMECYME 2020. Lecture Notes in Networks and Systems, vol. 143. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-53973-3_6 19. Cheng, G., Xiao, K., Wang, J., Pu, W., Han, Y.: Calculation of gear meshing stiffness considering lubrication. ASME. J. Tribol. 142(3), 031602 (2020) 20. Forrester, A.I.J., Sobester, A., Keane, A.J.: Engineering design via surrogate modelling: A practical guide, p. 4. Chichester, U.K, John Wiley & Sons Ltd (2008)
“ICDBY3D” Intelligent Component Development for Gas Turbine by Using 3D Printing at Siemens Energy AB Sweden Pajazit Avdovic(B) , Mineta Galijasevic, Vladimir Navrotsky, and Andreas Graichen Siemens Energy AB SE, 612 83 Finspong, Sweden [email protected]
Abstract. With great certainty, it can be said that there is no area that has gathered and influenced the new directions of development and manufacturing, as is the case of Additive Manufacturing. Digitization, automation, robotics, software, signal technology, and monitoring, analytics are some of the more prominent areas closely related to Additive Manufacturing. In addition, Digital Twin and Big Data are new directions that have emerged in parallel in the development of Additive Manufacturing. Computer Tomography, Virtual Reality, Augmented Reality, and Artificial Intelligence are initiated areas that came in close connection with Additive Manufacturing. Currently, Siemens Energy is mainly using this technology for prototyping, manufacturing, repair of gas turbine components, and spare part manufacturing [1, 2, 3, 4]. Additive manufacturing is considered a new revolutionary method and an integral part of Industry 4.0 contributing to major changes in the manufacturing process. It is interesting to consider the aspects and results of the development achieved in this specific area in a very short time interval. At the same time, it is very important to note a development and change of job description in the physical sense. The introduction of Additive Manufacturing has influenced the design process of new components and created freedom of thought in its application. Enormous opportunities have been provided to design details with a high degree of completeness with the use of new materials as well as programs that support the whole process. Through a new mindset, Additive Manufacturing has contributed to components being designed in a completely different way and given a completely different appearance and new intelligence -intelligent components (IC) implementation have further enhanced the components in compatibility and usefulness. The development of Additive Manufacturing is largely based on very close collaboration between universities, research institutes and industry. These three stakeholders are the main pillars for rapid and successful development where theoretical knowledge from the University are tested, validated, and implemented in industry fostering closer collaboration, knowledge sharing and development. Expanding knowledge, promoting innovation, and fostering cooperation in the Additive Manufacturing sector have been our key strategic levers to advance our mission in areas such as decarbonization, attaining further sustainability both in our own operation and in our product portfolio. Keywords: Additive Manufacturing · Digitalization · Digital Twin · Robotics · Automatization · Gas turbines development · Decarbonization · Intrapreneurship
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 286–300, 2021. https://doi.org/10.1007/978-3-030-75275-0_33
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1 Introduction Additive Manufacturing or 3D printing is a production method of a recent date that, with great security, takes its place in the processing of metals, plastics, and other materials. As a new method, it has caused a great deal of discussion about its importance and its position in machining processes. Some see it as a method that will replace other methods, while others count it as an integral part of the production system. It is quite clear that this method will replace or complement production processes in some components. There are already clear results of applications produced with this method such as greater efficiency and lifetime improvements. This manufacturing method can be used as the main alternative to produce many different components. Additive manufacturing is widely used in manufacturing parts with complex design that cannot be easily produced using conventional machining methods. It is important to note that the method offers great opportunities to improve certain features of components, such as: use of different media, improve mechanical properties, extended life, reducing the number of components and weight [5]. The method itself has contributed to a change in thinking about component design (Design for AM) and changes in organizational structure. If we start from the interpretation of the machine process [6] then Additive manufacturing can be explained with simplicity by a Fig. 1, where a Cad model is an Ideal structure which is produced into a workpiece as a realistic structure by the use of a system consisting of machines, powders and processes. However, there will be deviations caused by the manufacturing process, that may require adjustments and actions to alleviate to recreate the ideal structure from the Cad model. There are many ways to analyze these factors both within a factory by using internal resources or by collaborating with other agents such as universities, research institutes, and companies that face similar problems. This has generated several joint projects over several years, involving resources that have good knowledge in the AM area, resulting in many joint contributions to overcoming issues and creating new solutions.
Fig. 1. Closed-loop dynamic system of AM
When discussing AM, some central aspects to this method are important to highlight, such as the new way for designing the components. The classic rules of design somehow cease to apply while at the same time clear advantages in using this method -AMbrings totally new possibilities. In the embracement of AM, the question “why would we change a method that works so well” is no longer asked and instead a creative debate starts. This psychological moment of having removed the prejudice, is very important for
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the implementation of the method in existing processes. Even though there is quite a long implementation time required, it clearly leads to improved results. The prerequisites for the introduction as well as the functioning of this method in the best way, must simply be met. Two of the most important pillars for success is the organization and its leadership, who provides important support in both encouragement and financing. The method has already been tried and tested but the implementation process requires the procurement of machines, material certification, testing and many other related operations. As we have emphasized earlier, to be successful in implementing of this method, preconditions are required. In 2016, Siemens Energy included this method as one of the focus areas and with implementation of a new workshop, and a new era in area of Additive Manufacturing (Fig. 2) started.
Fig. 2. AM workshop as new era in area AM
Additive Manufacturing is the official industry standard (ASTM F2792) for all technology applications. Additive manufacturing is defined as the process which joins materials and creates objects from the 3D CAD model. The component is built by using the method layer by layer, which is in large contrast to subtractive manufacturing methods [7]. Additive manufacturing is a very dynamic process, with high velocity, light emission with wavelength range (VIS); infrared (IR) and ultraviolet (UV). Each AM process is defined by process parameters such as power and scan speed. During the printing process such as thermal process the constituents of metal powder changes from a solid substance to a liquid substance there in the melting of the material some local disturbances by vapor, spatter and overheat normally occur.In the process, protective gas is used with its flow. Protective gas and gas flow are an important factor for process stability and for component quality. AM is radiation-based manufacturing where the task of the protective gas in addition to creating an inert atmosphere, also removes bi-products from the process (splashes, smoke, etc.) Fig. 3. If during the process, insufficient or inhomogeneous inert gas flow occurs, the laser is weakened by interaction with the biproducts. In such cases, the biproducts that are not removed, will appear on the surface of the component, which in the next layer is covered with fresh powder and again processed with the laser. This results in undesirable deviations in the component properties and affects the process gas composition on the depth of penetration and the interaction with the processed material. The process speed affects the final surface profile as well as metallurgical properties of
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the molten material, mechanical-technical properties and may vary depending on the gas mixture. Gas supply (connecting pipes, gas tanks etc.) and the quality of the gas can also affect the result [8].
Fig. 3. Overview of possible by-products and their effects in laser-based additive manufacturing [9]
Comparing 3D printing (Additive Manufacturing) with Substrative Manufacturingconvectional Cutting methods, we can see how many different 3D methods have been developed on the principle such as Selective Laser Melting (SLM), Electron Beam Melting (EBM), laser cladding, binder jetting, etc. in the processing of metals, plastics, glass and other materials. At the same time, hybrid operations have developed in form as a combination of substrate processing and additive manufacturing. On the other hand, if we analyze Substrative methods, various operations have developed within various methods (turning. milling, drilling), while in the case of additive manufacturing, the completely new methods have been developed.
2 Intelligent Component 2.1 The Basis of Future Production The basis of future production and other systems are intelligent components. This term refers to self-contained, autonomously functioning mechatronic assemblies. They optimize the process thanks to their increased functionality from the set-up stage through to ongoing operations. Future systems are based on autonomously functioning mechatronic assemblies. In competition with a combination of sensors, actuators as well as data processing and communication, these assemblies are also referred to as intelligent components. These networks, organize and configure themselves to take orders from the superordinate control level. The technological challenge when developing intelligent components is the reduction of high-performance embedded systems. An Intelligent Components (IC) is an object that
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includes different types of knowledge corresponding to different levels of abstraction. The types of knowledge relate to different aspects of the product, such as shape (e.g., dimensioning rules), functional meaning, material, etc. [10]. Intelligent Component (IC) Development involves a set of related activities that include hardware, software, resources, information as well as energy factors in order to produce one component in the shortest time, minimum cost and with the best possible features while preserving the environment in which it is produced. One Intelligent Component should have the ability to send vital information about itself during its use such as operating safety, operating hours, operating conditions, replacement period, etc., all of which are considered basic operating parameters. 3D printing is increasingly entering in the production of parts in areas where conventional methods have played a leading role. At the same time, 3D makes a great contribution in the field of production such as: • Protection of human environment • Decarbonization • The use of Hydrogen as a fuel Additive Manufacturing (3D) provides some benefits and can be implemented in practice by usage of Design with freedom, possibilities for joining several components, x number of different components were all components, merged into only one component (Fig. 4(a)). The development of this method is highly dependent on one of the basic parts of the AM process, which is the powder material. As an example of this, additive manufacturing is supporting the development of combustion technology, Fig. 4. This production technology overcomes the challenges of hydrogen applications by allowing the creation of complex cooling features and fuel routing that would not previously have been possible. Through Additive Manufacturing an opportunity is opened where advanced fiber optics can be placed inside the components through the channels, Condition measurement at well-selected positions can be done in a way that was previously impossible Fig. 4 [11]. By installing sensors, it is possible to monitor the components during operation and consequently, in real time decide when the replacement of components is necessary. In practice this means the maximum use of one component is achieved. In addition, the use of the data obtained from these sensors, the method provides opportunities for a completely new design of these parts and with improved capabilities. E.g. parts exposed to high temperatures and through a new design improve their cooling system. Figure 4 explain the development way from one conventional produced component to Intelligent designed and produced component. a) b) c) d)
Old design of burner New designed component of Burner Using of Fiber Bragg Gratings (FBG) for temperature measuring Using of micro sensors for temperature measuring
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Fig. 4. iBuMa (Intelligent Burner Manufacturing)
2.1.1 Design There are some other activities included in Design area which contribute to manufacturing of intelligent components by Additive Manufacturing. Activities for adapting and optimization the design through Additive Manufacturing helps us to take advantage of this production method and therefore manufacture components which cannot be manufactured by conventional methods. The results from the research about Lattice Structure Fig. 5, provide the opportunity to create lighter products which can be integrated into structures that have been optimized (through e.g. topology optimization, TO) to increase the robustness for e.g. loads in directions not intended or included in the design.
Fig. 5. Lattice structure and topology optimization
The ability to print the very thin walls of a lattice structure is considerably complicated but an essential design as part of the cooling functionality of the turbine component. In achieving this, the confidence in AM as production method has been achieved without changing the properties of the component, Fig. 6. By far, AM offers the greatest opportunity in the freedom of design to facilitate weight savings, which so far have been difficult or impossible to achieve with conventional manufacturing.
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Fig. 6. Possible demonstrator from Siemens, a structure for the hot gas path (guide vane).
2.1.2 Material In parallel with the design development and development of the printing process it is also important to develop the material in the form of powder, especially new materials for printing of Turbine components. Advanced Ni-based superalloys with excellent creep and oxidation properties, have been found to be very difficult to use in the printing of Turbine Components without significant cracking problems [12]. The level of material’s porosity is dependent on several process parameters that potentially can affect the AM processes. Optimization of the process parameters is there for necessary for all materials to achieve high quality of the built-in component. The use of graphene, nanotechnology and smart materials is a good basis for the realization of Intelligent Components (IC). Graphene is one of the world’s thinnest materials and in flexible, much stronger than steel and has very good conductivity. These characteristics makes Graphene a highly suitable material to be used in sensors, to reduce friction between surfaces and completely tight barriers. Graphene is included in a group of smart materials - artificial materials that have one or more properties that can be significantly altered in a controlled manner by external stimuli, such as mechanical stress, temperature, light, moisture, pH, electricity, or magnetic fields [13]. Powder metallurgy as a green technology has a high growth potential, as it can address needs in different sectors in society. Currently, Sweden leads the way in the sector, with about 25–30% of the world metal powder production being based in the country. 2.1.3 New Area – Decarbonization Decarbonization refers to the reduction or elimination of carbon dioxide from energy sources. There are several levels of decarbonization where the fastest is to upgrade existing products to make them more efficient thereby reducing the emissions of various gases, such as NOx and CO2 . Siemens Energy is in an optimal position given the technology and know-how in the new design of turbines and compressors to meet these and future requirements. Additive manufacturing (AM) has been a huge driver of innovation across many industries. In the past few years, we’ve been able to acquire a lot of practical expertise in this field [14] and it is an excellent opportunity for us to go from a standard version to AM optimized design where the traditional manufacturing limits flexibility and functionality.
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Right now, there are some components (blades, burners etc.) that with full certainty will enable turbines to achieve zero net emissions, switching to clean energy sources and climate stabilization. One important aspect of AM as a production method is that these intelligent components (IC) contributed to a better environment through optimized production process, not only as finished and improved components, but also during the whole production process since this method enables minimal resource consumption of electricity, water, and material. 2.1.4 Digitalization Digitalization offers many current projects related to Additive Manufacturing where the goal is to increase the use of Additive Manufacturing as a production method by integrating AM technologies into a complete production flow. Additive Manufacturing (3D printing) offers wide and free flexibility in product geometry, giving a lot of opportunity to customize different component designs to find the optimal design. Visualization of AM (Fig. 7) shows how the printing process gives us possibility for using the pictures from 3D printing machines. The created model can be used for inspection of the component after manufacturing. The main target is to enrich the existing solid CAD model with information about the SLM process.
Fig. 7. Visualization off AM process
Computed tomography (CT) Fig. 8 is the most effective technology for nondestructive testing. The development of the CT technology is suitable for further inspection of printed components.
Fig. 8. Inspection of component by using of CT
The automatization of Additive Manufacturing improves and increases the level of use of the AM method. The second aspect in automatization is how to build a smart factory. Increasing the level of automatization in quality is characterized by processes for selected workpieces and associated tools as well as logistics operations. These generate large amounts of data that can be used for analysis and prediction as well as to optimize the quality of manufacturing operations and manufactured products.
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Many application scenarios can significantly benefit from the techniques [15] such as robotics, electronics, automotive, aerospace etc. The use of robots (collaborative robots) together with digitalization, is becoming increasingly important and is a necessary part of Additive Manufacturing. Robotic use has several benefits in production, such as less impact on health and environment, continuous production, and improved quality. There are many activities that today’s robots can perform such as: positioning, picking up the nozzle for vacuum cleaners, cleaning chambers, transportation and many similar activities Fig. 9. The vision is that workshops will only be manned by robots with little or no assistance from human interaction. So far, results of the work show tremendous potential for robot use.
Fig. 9. Collaborative robots for cleaning of chamber
Despite the positive momentum, the industry still has a long way to go on its digital transformation journey. However, times are changing, as it has become clear that the benefits of embracing disruptive technologies—such as artificial intelligence (AI), digital twins, and additive manufacturing (AM)—greatly outweigh the perceived risks [16]. The Siemens Energy AM Monitor Fig. 10, is adaptable to different systems and can be used for Root Cause Analysis identification process (RCA).This software can help to reduce post process inspection (Geometry, flow, Material testing), early rejection of bad parts and is deployable in-situ monitoring system. Fully deployed, this system
Fig. 10. Typical problem process development in AM monitor (powder drop)
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will be used in the identification and classification of Residual stress deflection, Local overheating, Condensate, Short powder feed and Powder drop. With the help of machine learning algorithms, an artificial, numerical judgement of each powder layer is introduced, called the “Severity Score”. It is a value between 0 and 1, with higher values indicating a higher probability of future process failure. Plotting this severity score over an x-axis gives the technician and engineer a quick way to focus on a problematic layer in the build and resolve that issue in a faster process.
3 Manufacturing of Components The integration of AM into the product development process enables significant speed up of design, validation of new components and system and ensures high reliability and performance of newly designed components prior to final engine test and product release. With the new approach, AM is an integral part of the development process and can be used for rapid component design and manufacturing. There are three different areas of use within AM: Rapid Prototyping, Rapid Manufacturing and Rapid repair. With the introduction of SLM technology in gas turbine repair back in 2013, Siemens Energy took the first step to bring the new technology out of the laboratory into an industrial production environment. Subsequently, Siemens Energy went on to launch the first burner repairs using SLM technology which today is in serial production, Fig. 11. Repair of components has also been identified as an application with big potential.
Fig. 11. RaBuTiR (Rapid Burner Tip Repair)
For Siemens Energy, the industrialization of AM technology also enables new opportunities for spare part and supply chain enhancement.
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One of the first successful applications of AM serial manufacturing at Siemens Energy, was the manufacturing of advanced burner swirlers for the SGT-750 industrial gas turbine as shown in Fig. 12.
Fig. 12. Advanced burner swirl manufactured by AM for SGT-750 industrial gas turbine
Following the integration of 3D-printing as part of its digital services portfolio, Siemens Energy has achieved an industrial breakthrough with the first successful commercial installation and continuing safe operation of a 3D-printed part in a nuclear power plant. The replacement part produced for the Krsko nuclear power plant in Slovenia is a metallic impeller for a fire protection pump, as shown in Fig. 13, that is in constant rotating operation. Siemens Energy’s team of experts in Slovenia reverse-engineered and created a “digital twin” of the part. The company’s additive manufacturing facility in Finspong, Sweden, then applied its advanced AM process using a 3D-printer to produce the part. A Siemens Energy designed and manufactured water pump impeller using Additive Manufacturing and 3D-printing is now in operation in the Krško nuclear power plant.
Fig. 13. First 3D- printed impeller for a fire protection pump for the Krško nuclear power plant
Successful production of components for Nuclear Power continues with two new components Clapper and Clapper holders (Fig. 14).
4 Research in AM The development of the AM method, in addition to special investment for development, requires a high level of cooperation with universities through various projects or special
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Fig. 14. 3D-printed components for the nuclear power plant
tasks. A wide range of topics (material, processes, software, signals, data, and more) are included in various projects, which greatly contributes to the development of the method with the goal of creating a secure process called “Robust Process”. The robust process is explained as a process where printing activities take place regarding downtime, special interventions, and similar disturbances. The map of cooperation with Universities, research institutes as well as companies is shown in the Fig. 15 and represents the way on which that cooperation is based. There are four main areas of cooperation: Material, Processes, Applications as well as Digitization. In addition, collaboration is based on three levels: Generic, Applications as well as Advanced Development.
Fig. 15. University & research institutes collaboration
Siemens Energy’s investment in additive manufacturing (AM) can clearly be viewed as a result from intrapreneurship within the company, where many areas have been developed as a result of implementing AM. This can be seen from the creation of new organizational setup to investing in development in new advanced technology and through important collaborations with other firms and universities. Research [17] brings out the importance of intrapreneurship for the organizational survival, profitability, growth, and
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renewal. Generally, the reasons for why companies engage in intrapreneurship are to seize opportunities both as a complement but also to extent their existing business, to utilize resources in more effective way, to motivate employees and to retain managerial talent [18, 19]. Organizations with strong focus on intrapreneurship are usually viewed as dynamic and flexible with the ability to take advantage of new business opportunities [20]. Clearly additive manufacturing (AM) has brought new opportunities for Siemens Energy and will continue to evolve, from new application areas, material, and development to new business model creations.
5 Discussion and Conclusion Successful development of the AM technique requires close cooperation with the Universities, research institutes, as well as cooperation with companies also using this technique. At the same time, it is very important to have a clear strategy regarding the use of this method. There are several factors to consider here such as: • Clear definition of vision and realistic goals depending on the need, time, and cost • Adapt the visions and goals based on the need, not the need based on the visions and goals • Motivation to implement consists of external forces and internal strategies. • High level of cooperation within the organization between R&D, production and other functions is needed. • A deep root cause analysis of why AM has not succeeded with the production in different form as recommended. • Further on, the use of robots (collaborative robots) in Additive Manufacturing together with Digitalization is a topical focus. The cooperation that Siemens Energy has with Universities, Research Institutes and companies have resulted in many projects, forums, which in turn has resulted in the constant increasing of number of printed components in Additive Manufacturing. Practically and with great certainty it can be said that 3D contributes to the development of products in form as Intelligent Component (IC) and organizational structures of companies where complicated components are produced without major problems. It has enabled the integration of components from several parts into one component- functional integration, printing on existing component. Further to this, it is now possible to integrate alternative technologies into printed components by installing optical fibers in the components as well as the installation without wired microsensors that are installed in the printed components during the process. At the same time, Additive Manufacturing has opened possibilities for the use of alternative fuels in gas turbines, thanks to new constructions of printed components where turbines of a new character and features are being developed at the same time. The company has far-reaching plans to make AM production even more flexible by decentralizing it. In the future, there may well be 3-D printers at Siemens Energy’s service centers worldwide for printing replacements and new parts locally. The era of large warehouses full of pre-manufactured components waiting to be shipped to
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customers is ending. The idea is to print components wherever Siemens gas turbines are located, worldwide [21]. Additive manufacturing enables the integration of “Artificial intelligence” (AI) trough Machine Precipitation, Machine Learning, Natural Language Processing (NLP), Knowledge Representation & Reasoning, Automated Planning, and Intelligent Robots [22]. The future of Additive Manufacturing can be summed up as being a mainstream technology for serial production with design software will be more integrated and easier to use, thus expanding into new areas and services as well as developing new materials and automation opportunities. The implementation and industrialization of AM technology at Siemens Energy resulted in a significant impact not only on to design and validation of SE gas turbines and their components, but also on to manufacturing process transformation. Integration of AM technology into design and manufacturing enables several design iterations in just a few months instead of years. In case of conventional design and manufacturing process the new products test and validation was performed at the end of the process with the following consequences: • • • •
sequential development process, conservative development approach, moderate development targets/results, long development cycles with a risk to redesign some components after tests and validation. While new approach foster:
• • • • •
parallel and integrated development, manufacturing, and testing processes, radical development approaches, ambitious development targets/results, fast development cycles, low risk for redesign.
The setup of AM workshop at SE created not only additional workplaces, but new environmentally friendly production. Siemens Energy evaluation showed, that in average, for components that were manufactured by AM the emission related to production method was reduced by 30% compared to conventionally manufactured components. Today Siemens Energy delivers to the market gas turbines with AM manufactured components in the combustors and turbine modules.
References 1. Navrotsky, V., Graichen, A., Brodin, H.: Industrialization of 3D-printing for gas turbine components repair and manufacturing. In: VGB Conference, Gas Turbine and Operation of Gas Turbines 2015, Lübeck/Germany, 06–07 May 2015 (2015) 2. Brodin, H., Navrotsky, V., Graichen, A., Brodin, H.: 3D-printing at Siemens Power Generation service. In: Total Conference, Paris, France, 17 December 2015 (2015)
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3. Navrotsky, V., Graichen, A., Brodin, H.: 3D-printing at Siemens power generation service. In: 3D-Printing Technology, Las Vegas, USA, 18 February 2015 (2015) 4. Navrotsky, V., Piegert, S., Andersson, O., Graichen, A., Avdovic, P.: Industrialization and current field experience of additively manufactured gas turbine components. In: 9th International Gas Turbine Conference, Brussels, Belgium, 10–11 October 2018 (2018) 5. Felix, A., Peter, B.: Developing hydrogen combustion-based concepts for heat and electricity generation—concept generation, evaluation and selection from case specific preconditions at Siemens industrial turbomachinery AB in Finspång. Linköping University Department of Management and Engineering Master thesis (2019) 6. Archenti, A.: A computational framework for control of machining system capability from formulation to implementation. KTH Royal Institute of Technology, Stockholm, Sweden, Doctoral thesis (2011) 7. Bandyopadhyay, A., Bose, S.: Additive Manufacturing. CRC Press, Florida (2015) 8. Jahn, S.: Steigerung der Leistungsfähigkeit des Selektiven Laserstrahlschmelzens durch den Einsatz von angepassten Prozessgasen: Schlussbericht. DVS, Jena (2014) 9. Ladewig, A., Schlick, G., Fisser, M., Schulze, V., Glatzel, U.: Influence of the shielding gas flow on the emoval of process by-products in the selective laser melting process. Addit. Manuf. 10, 1–9 (2016) 10. Suscat, L., Mandorle, F., Rizzil, C.: How to Represent “Intelligent” Components in a Product Model A Practical Example) 11. Havermann, D., Mathew, J., MacPherson, W.N., Maier, R.R.J., Hand, D.P.: Temperature and strain measurements with fibre Bragg gratings embedded in stainless steel 316. J. Lightwave Technol. 33, 2474–2479 (2015) 12. Chauvet, E., et al.: Hot cracking mechanism affecting a non-weldable Ni-based super alloy produced by selective electron beam melting. Acta Mater. 142, 82–94 (2018) 13. Elf, C.: Smarta material. www.claraelf.com. https://www.claraelf.com/smartamaterial.html 14. Holt, T.: Spring issue of Diesel & Gas Turbine Worldwide magazine, 22 April 2020 15. Li, X., Siahprur, S., Lee, J., Wang, J., She, J.: Deep Learning-Based Intelligent Process Monitoring of Directed Energy Deposition in Additive Manufacturing with Thermal Images 16. Originally appeared in World Oil®, p. 23, November 2019 17. Zahra, S.A.: Goverance, ownership, and corporate entrepreneurship: the moderating impact of industry technological opportunities. Acad. Manage. J. 39(6), 1713–1735 (1996) 18. Pinchot III, G.: Intrapreneuring: Why You Don’t Have to Leave the Corporation to Become an Entrepreneur. University of Illinois at Urbana-Champaign’s Academy for Entrepreneurial Leadership Historical Research Reference in Entrepreneurship (1985) 19. Zahra, S.A.: Predictors and financial outcomes of corporate entrepreneurship: an exploratory study. J. Bus. Ventur. 6(4), 259–285 (1991) 20. Kuratko, D.F., Ireland, R.D., Covin, J.G., Hornsby, J.S.: A model of middle–level managers’ entrepreneurial behavior. Entrep. Theory Pract. 29(6), 699–716 (2005) 21. Torbjörn Fors-B2B Portal for Techical and Comercial Foundry Management (Foundry Corporate News-Topics 3D Printing,) 25 April 2017 22. 2020 Manufacturing in the Age of Artificial Intelligence
A Comparison of the CMM and Measuring Scanner for Printing Products Geometry Measurement Almira Softi´c(B) , Hazim Baši´c, and Kenan Balji´c Faculty of Mechanical Engineering, University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina [email protected]
Abstract. The paper presents an analysis of a product made by 3D printing using CMM and a measuring scanner. Special attention is paid to the comparison of the CMM measurement and scanner with the aim of optimal selection of measurement method depending on the measuring object characteristics which need to be obtained. For the purpose of comparing measurement methods, the product was made using 3D printing technology (FDM) based on 3D CAD model which will serve as a reference basis for measuring deviations on actual model. CMM on which the measurement was performed is a five-axis CMM (three translational and two rotational degrees of freedom) manufactured by Hexagon. The software used on the CMM is PC-DMIS 2018. Scanning was performed with a structured light scanner from Steinbicher using the required softwares (Colin3D, InspectPlus and GOM Inspect). A direct comparison of the measurement procedures on the CMM and the scanner of one product obtained on a 3D printer is given below. Keywords: CMM · Measuring scanner · 3D printing products
1 Introduction When developing prototypes, additive production techniques (3D printing) are commonly used today, primarily due to the shortening of product development time. After making the product, it is often necessary to check the dimensions of the workpiece, quickly and accurately so that the necessary corrections can be made (if necessary). Contact and non-contact inspection devices are used widely. Today, CMM and measuring scanners are most commonly used to accurately check the dimensions of a workpiece. Selection of the optimal measuring method is very important because it affects on accuracy and speed of measurement and cost of product development. With the development of technology in the 1980s, contactless 3D measurement procedures appeared. Thus, the aim was to speed up the measurement process as well as to avoid physical contact [1]. An example of possibility of measuring a small objects, namely hard metal rod which is a semi product for cutting tool, e.g. end mill is given in [2]. CMM represent one of the most accurate and flexible measuring instrument used in metrology field. The precision of the CMM when measuring distances between planes © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 301–309, 2021. https://doi.org/10.1007/978-3-030-75275-0_34
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does not depend on the position they were located at, as in [3]. 3D scanning technologies are used to convert a physical model into digital 3D computer-aided design (CAD) file where this digital output is well used for designing and fabricating customized parts through additive manufacturing technologies [4]. A successful example of integrated reverse engineering and rapid prototyping approach towards reconstruction of damaged impeller using scanner is given in [5]. Many parameters affect the dimensions of products made by additive technologies [6].
2 3D Printing Model for Measuring Methods Comparison For the needs of the analysis of the measurement process, a workpiece was specially made by the FDM printing method. Product is designed on SolidWorks and STL file (Stereolithography) was uploaded to 3D printer. In order to obtain the minimum deviation of the measuring object from the nominal geometry, the recommendations from the research [7] and [8] were used. The product is made on an Ultimaker S5 printer from PLA polymer. The thickness of the layer of material during printing was set to 0,1 mm. Fig. 1a shows 3D CAD model and Fig. 1b shows 3D printed model.
Fig. 1. a) 3D CAD model of measuring object b) Actual 3D printed model c) Overall nominal dimensions and hole details of measuring object
Overall nominal dimensions and hole details of measuring objects are shown on Fig. 1c. Function of chamfer on one corner of measuring object is to makes it easier to automaticaly match scanned pictures. Measuring object has 96 holes (nominal dimension Ø7 mm), and every hole has four symetrical bumps inside as it is shown on Fig. 1c.
3 Measuring Object Aligning Prior to any measurement using the CMM, it is necessary to place the coordinate system on the measuring object. After that, the final alignment is set where the points used to
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align coordinate axes will be performed in automatic mode. In this way, it is ensured that the approach of the measuring probe to each point is made normally to the surface. This way probe will always approachto measuring object with programmed speed in area of prehit/retract and alignment errors will be minimized. Figure 2 shows measuring object placed on worktable of CMM and process of alignment using 321 method. Since the CMM works on the contact principle, all the necessary alignment points must be reached with a measuring probe and it’s clear that this requires time.
Fig. 2. Selecting points to define alignment define plane on CMM
Fig. 3. Automaticaly selecting plane to alignment using scanned geometry (STL file).
Measuring scanner works on a contactless principle, and results of scanning is mesh (STL file) which is created from surface points of measuring object. Alignment on created mesh can be set using apropriate softwares as Colin3D, InspectPlus, GOM Inspect and others. A big advantage of using the measuring scanner is that surfaces of measuring objects can be generated using all the points obtained by scanning that surface as shown in Fig. 3. This method of aligning represents better surfaces of measuring object due to the large number of points. Selecting a large number of points on the surface using CMM is also possible, but it requires a lot of time because each point needs to be reached with a measuring probe. Characteristic of products made with FDM printer are noticeable layers in the direction of product thickness and it can affect the measurement results. Also, that is another advantage of the measuring scanner, primarily in the fact that a plane can be created using all scanned points of measuring object. Plane can be created that the sum of squares of deviations of all scanned points from the ideal plane is minimal. This way, dimensions on measuring object are created using ideal planes which represents the characteristic dimensions of the measuring object.
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4 The Measurment Differences To measure specific dimensions on measuring object using CMM, it is necessary to previously specify required elements of geometry to which the required dimensions of the measuring object are related. Measuring the distance between parallels is possible by creating two lines on the planes between which the distance is measured, but then one should be aware that a smaller number of points on the plane is less representative of the same. Figure 4a shows an example of selecting line on the right side, and Fig. 4b shows selecting line on the left side with the aim of measuring distance between two parallel planes. Distance is determinated using two lines which are located on the planes between which the distance is measured. Due to the limited access of the measuring probe to the measuring object, the measurement was performed between two lines as opposed to two planes.
Fig. 4. Selecting lines for measuring distance between two planes on CMM a) on the right plane b) on the left plane
In this example another disadvantage of measuring with CMM can be observed. Due to the small height of the wall of the measuring object, it is not possible to use a measuring probe of large diameter, otherwise the measuring probe will reach the bottom base of the workpiece. On the other hand, the diameter of the measuring probe also defines the points at which it is possible to access the measuring surface. In the given example, a measuring probe with a diameter of 1,5 mm was used, and accordingly, all points below half the diameter on the specified plane cannot be reached with the measuring probe. When using measuring scanner, to measure distance between two planes it is enough to create two planes with just one click on the surface, and the measurement software (InspectPlus or GOM Inspect) automatically generates a plane using all points on that surface as it is shown on Fig. 5a. It is also possible to create a plane by clicking on individual points, but a better representation of the results requires a larger number of points of the measuring object. Therefore, since the measuring scanner works on the non-contact principle, those surfaces to which the structuring light falls will be registered and the points on them are used to create geometric elements in order to represent the measuring object. The problem of the contact method of measurement is noticed again when it is necessary to mark the plane on the workpiece shown in Fig. 5b. The plane is 1,2 mm
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Fig. 5. a) Selecting planes for measuring distance between two planes on scanner b)_automatic selection of 1,2 mm wide plane
wide, so it is not possible to select it with a measuring probe with a diameter of 1,5 mm. Therefore, when measuring on the CMM, it is necessary to have a larger number of measuring probes of different diameters that can be accessed on the surfaces of the measuring object. The purchase of measuring probes requires additional costs. 4.1 Measuring Holes with Bumps As it’s shown on Fig. 1c every of 96 holes in measuring object has four symetrical bumps. When measuring diameter of holes using CMM, measuring probe must be enought small to get into hole. To measure a diameter using CMM, at least 3 points on cilinder needs to be selected with measuring probe. For better representation of the geometry of the holes, the diameter of the circle was measured at 8 points as shown in Fig. 6a. It is necessary to adjust the approach trajectory of the measuring probe so that it does not touch one of the four protrusions inside the hole and thus lead to incorrect measurement results. The disadvantage of measurement with CMM is that the diameter is obtained only in one plane of the measuring object. It is clear that the products obtained by printing are made in layers, which leads to variations in the diameter of the hole according to its height. Therefore when fitting the measuring objects, the results obtained in this way do not represent the cilinder of the workpiece, because results shows diameter of the hole only in one plane. When measuring diameter of holes using scanner and appropriate measurement software, cylinder can be generated automatically using points on reference geometry contained in STL file. Figure 6b shows that the results of measuring of hole diameter obtained using all scanned points (red cylinder area). If there exist a 3D CAD model of the measuring object, after alignment CAD model with scanned object, the softver has no problem with recognizing the cylinder despite the protrusions, so all four protrusions inside the hole will not be considered as it can be seen on Fig. 6b. The problem of changing the diameter of the hole with height is also visible in Fig. 6b where a slight increase in the inner diameter can be noticed at the top of the measuring object. When scanning the measuring object, for one orientation the measuring object on rotary table the structuring light could not pass to the bottom of the hole so the continuation of the hole is not visible on the created STL model (Fig. 6b). By repeating the scanning process with a different orientation of the measuring object on the rotary
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Fig. 6. Measuring hole diameters a) selection of contact points on the measuring object using CMM b) using GOM Inspect and scanned part geometry
table, better aperture representations can be obtained. Small diameter holes have limited depths that can be scanned, so in that case it is more convenient to use CMM since contact probes are made with different heights. Accordingly, places that cannot be reached by structuring light cannot be measured. When using measuring softvares as InspectPlus the measuring object can be intersect with arbitrary levels and observe the geometry at intersection places. This is especially convenient when checking workpieces made with 3D printing because it can be easily to monitor a change of the hole diameter in function of height. Figure 7 shows a crosssection of the measuring object with a horizontal plane where a shrinkage in the produced diameter can be observed in relation to the nominal geometry. It can also be seen that all four protrusions were not made as on the CAD model (as it’s shown on Fig. 1c) but had a significant rounding of the edges. This curvature may affect the results obtained by the CMM if the measuring probe did not avoid the protrusions when manually adjusting the measuring probe trajectory.
Fig. 7. Nominal and actual shape of the hole with grooves (InspectPlus)
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4.2 Measuring Elements with Significant Deviation from CAD Model If the printed models have a significant deviation from the nominal CAD model, this can be a problem when measuring with CMM. The reason is that the measuring probe always automatically approaches the measuring object in order to select points for defining the reference geometry. If the point isn’t within certain limits the measuring probe cannot automatically find reference points and it is necessary to manually show CMM where the point of measuring object is located. This process requires interrupting the DCC mode of the machine and switching to manual mode. Problem could be noticed on the manufactured product on 4 cylinders on the upper part of the measuring object. Anomalies in the shape of the cylinder itself were visually observed as shown in Fig. 8. When using a measuring scanner, using a comparison with a nominal CAD model deviations of the fabricated model can be clearly observed. The deviation labels (shown at Fig. 9) indicates deviation of actual model relative to the CAD model. At the top of the cylinder, the location where the nozzle finished printing can also be clearly seen.
Fig. 8. Visible defects on the measuring object
Fig. 9. Results of defects using a measuring scanner (InspectPlus)
The most significant feature of the scanner is the simple Best-fit alignment of the entire model where the characteristic deviations of the manufactured model from the nominal CAD model can be graphically displayed. Deviation labels show deviations from the nominal geometry at characteristic points as it’s shown on Fig. 10.
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Fig. 10. Best-fit alignment on scanned geometry and comparation with nominal CAD model (GOM Inspect)
5 Conclusion When producing small parts with small details with FDM technology, it is clear that they cannot be made as a CAD model without deviations. The problem of using CMM in measuring small parts is reflected in the approach of the measuring probe to individual surfaces in order to determine the reference geometry. It is clear that the CMM shows greater accuracy when measuring larger measuring objects (because the measurement uncertainty is known within the measuring range of the CMM). This advantage is not reflected in measuring 3D printed objects because most 3D printers are designed for production parts of limited dimensions. FDM printing is characterized by frequent problems with the production of small details, so their measurement with CMM can cause many problems and complicate the measurement process. When measuring on the CMM, the second piece cannot be measured until all the reference points for determining the geometry of measuring object have been determined by the contact probe. To scan larger parts, it is necessary to use lenses and projectors to capture a wider image, which leads to the fact that small details on the measuring object are not best represented. Measurement speed is the main advantage of the measuring scanner. The scanning process takes a few minutes and the result is a file that contains all the characteristics of the measuring object reached by the structured lighting. Generated scanned model can be transferred to an external computer to determine the dimensions and thus reduce scanner busy time. Scanning objects with deep holes of small diameter can be a problem due to the inability to propagate structuring light to the bottom of the hole.
References 1. Stojki´c, Z., Culjak, E., Saravanja, L.: 3D measurement – comparison of CMM and 3D scanner. In: DAAAM International, Vienna, Austria, pp. 1726–9679 (2020) 2. Vagovský, J., Buranský, I., Görög, A.: Evaluation of measuring capability of the optical 3D scanner. Procedia Eng. 100, 1198–1206 (2014) 3. Puertas, I., Luis Pérez, C.J., Salcedo, D., León, J., Luri, R., Fuertes, J.P.: Precision study of a coordinate measuring machine using several contact probes. Procedia Eng. 63, 547–555 (2013)
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4. Lazarevi´c, D., Nedi´c, B., Jovi´c, S., Šarko´cevi´c, Ž, Blagojevi´c, M.: Optical inspection of cutting parts by 3D scanning. Phys. A 531, 121583 (2019) 5. Jain, S., Hasan, F., Kumar, A.: An Integrated Reverse Engineering and rapid prototyping approach towards reconstruction of damaged impeller. ResearchGate, pp. 393–404 (2016) 6. Azhikannichal, E., Uhrin, A.: Dimensional stability of 3D printed parts: effects on process parameters. Ohio J. Sci. 119(2), 9–16 (2019) 7. Dey, A., Yodo, N.: A Systematic survey of FDM process parameter optimization and their influence on part characteristics. J. Manuf. Mater. Process. 3, 64 (2019) 8. Gensler, M., Salehi, S., Boccaccini, A.R., Groeber-Becker, F.K., et al.: 3D printing of bioreactors in tissue engineering: a generalised approach. PLOS ONE 15, e0242615 (2020)
3D Printing Solutions in the Fight Against Covid-19 Pandemic Milena Djukanovic1(B) , Mihailo Jovanovic2 , Nikola Pejovic3 , and Dejan Lutovac3 1 Faculty of Electrical Engineering, University of Montenegro, Podgorica, Montenegro
[email protected]
2 Faculty of Business and Law, University of Union, Podgorica, Montenegro 3 Faculty of Mechanical Engineering, University of Montenegro, Podgorica, Montenegro
Abstract. The global pandemic, caused by COVID-19, brought the whole world to its knees in 2020. Medical systems worldwide succumbed due to the disease outbreaks while healthcare workers have been fighting at the forefront. Medical supplies were running out in many countries and countless lives were lost because of it. Engineers, inventors, and creators from around the world have teamed up to help this cause through 3D printing solutions. It is additive manufacturing that became a leading light in the fight against the COVID-19 as a go-to method in case of medical supply shortages. Keywords: 3D printing · COVID-19 · Solutions · Respirators · Ventilators · Face masks · Face shields · Spare parts
1 Introduction COVID-19 is a contagious respiratory system disease caused by the novel SARS-CoV-2 virus [1]. It first appeared in Wuhan, Hubei province, China at the beginning of December 2019 but it did not go mainstream until late January 2020. Ever since then, more than 90 million cases have been detected so far and it has taken almost 2 million lives worldwide. Multiple vaccines have completed their trial periods only a year after the first COVID-19 case was registered and they are starting to get distributed worldwide. COVID-19 has caused a complete medical system breakdown in numerous countries across the globe. Many of them have experienced medical equipment scarcity, especially with respirators and ventilators. Spare parts shortages have been reported worldwide so the engineers had to come up with different methods of using 3D printing to resolve this problem. This made 3D printing one of the key players in the fight against the COVID-19. In this paper, we will review the most notable global solutions from around the world with presentation of the situation in Montenegro and presenting their new innovative 3D printing solutions against the COVID-19 pandemic.
2 Solutions Worldwide Due to COVID-19, people around the world were forced to change their daily routines and pay extra attention to respect the safety precautions to protect themselves, their © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 310–322, 2021. https://doi.org/10.1007/978-3-030-75275-0_35
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families, and friends from such a harsh disease that took on the world like a wildfire. Just like regular people, companies were greatly affected as well. Unlike any other field, additive manufacturing, or in other words 3D printing, got its chance to shine by answering governments’ and medical industries’ calls to step up the production of medical equipment and devices amidst the worldwide shortages [2]. The advantage to 3D printing, in this case, is the fact that lately 3D printers became widely available and you do not even have to be an expert to use them. Most of the companies who contributed to the cause made their design files available on their website (open-source), so that volunteers from across the world can manufacture 3D printed parts that could end up saving many lives. Among the countless solutions and initiatives from almost every developed country, we have chosen five of the most interesting ideas from different countries that we ran across while doing our research. 2.1 China: 3D Printed Parts Designed to Help Healthcare Workers Relieve Stress Caused by Protective Equipment Farsoon Technologies is a Chinese supplier company that distributes industrial plastic laser sintering and metal laser melting systems. They shifted their focus towards the fight against the COVID-19 during the virus outbreak in China and with their partners, they continued to contribute to the cause worldwide by making their design files available for everybody to download [3]. Through the partnership with Farsoon Technologies, PEAK Sports designed the 3D printed facial mask adjustor (Fig. 1). This piece of equipment helps healthcare workers relieve the stress on their ears caused by wearing protective facial masks for extended periods. It consists of four pairs of hooks and a textured body that is compatible with different types of protective equipment.
Fig. 1. Farsoon’s 3D printed facial mask adjuster design concept
Using Farsoon Technologies’ systems, Huaxiang Group designed the 3D printed safety gogglesthat are notably lighter and more comfortable than the regular safety
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goggles (Fig. 2). Wearing these goggles reduced the stress caused by extensive wear of protective equipment by the healthcare workers who were at the frontlines of the battle against COVID-19. These safety goggles, which are available in two sizes, consist of a strap with an adjustable buckle, goggle sealing ring, protection lens, and safety goggle frame.
Fig. 2. Farsoon’s 3D printed safety google design concept
2.2 Italy: Turning Off-the-Shelf Snorkeling Masks into Emergency Respirator Masks Using 3D Printed Charlotte Valves Isinnova is an Italian startup company composed of engineers, designers, and communication experts who are engaged in the implementation of the ideas into action [4]. They used one of their creative ideas to help the fight against the COVID-19 while the Italian health system was hitting the rock bottom amidst the massive virus outbreak. Isinnova came up with an idea to transform the off-the-shelf snorkeling masks into emergency respirator masks for assisted ventilation using 3D printed Charlotte valves (Fig. 3). This emergency respiratory mask can be used with both continuous positive airway pressure (CPAP) respirators and regular wall-mounted oxygen distributors. The five steps that are necessary to make the mask work are: 1. removing the vent valve protection, 2. switching the front membrane from the outside to the inside into the same hole, 3. putting back the vent valve protection, 4. removing the two valves from the chambers around the nose, and 5. inserting the 3D printed Charlotte valve at the top of the mask in place of a regular mouthpiece. One end of the 3D printed Charlotte valve goes directly into the mask, the other one is used for the oxygen (O2) supply and the last one is for the positive end-expiratory pressure (PEEP) regulator connection (Fig. 4).
3D Printing Solutions in the Fight Against Covid-19 Pandemic
Fig. 3. 3D printed Charlotte valve
Fig. 4. Isinnova’s 3D model of the emergency mask for hospital ventilators
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2.3 United States: Challenge for Innovators to Use 3D Printing in Response to Spare Parts Shortages Across the Country CoVent-19 Challenge was a hackathon designed as a way to collect solutions to fight the shortage of ventilators and ventilator spare parts amidst the COVID-19 outbreak in the United States [5]. It was initiated by 13 anesthesiology residents of Massachusetts General Hospital who are experts in mechanical ventilation. The challenge was supported by the American-Israeli company Stratasys, which builds 3D printers and other 3D production systems, and a medical company Ximedica from Providence, Rhode Island, USA, which designs and develops healthcare products. Its main goal was to gather ideas for building cheap, easy to make, and remote ventilators that could support healthcare systems across the United States and abroad that were facing medical equipment shortages. This challenge proved that amazing things can be done when innovators from across the globe come together to fight for a common good. Among more than 200 submissions from around the world, seven finalists, shown in Figs. 5, 6 and 7, have been chosen. Baxter Ventilator was designed by a combined team of instructors, students, and former graduates of the Baxter Academy for Technology and Science in Portland, Maine, USA [6], (Fig. 5a). This device helps with the ventilator shortages amidst the pandemic since it can be made by craftsmanship laymen using common materials that can be found in regular stores. It can provide either assisted or controlled ventilation and it can be used both in conventional hospitals and in emergencies out in the field since it is completely remote. CORE Vent was invented by the winner of the Queen’s Innovation Award, Ross Hunter from a Scottish company “Armadilla Ltd” in Edinburgh [7], (Fig. 5b). His costefficient solution was targeted towards the developing countries without access to the ventilators through their countries’ healthcare systems. Just like Baxter Ventilator, it uses off-the-shelf parts and it is easy to assemble using the provided manual. Vox, originally labeled as InVent Pneumatic Ventilator, was built by two companies from San Francisco, California, USA [8], (Fig. 5c). The first company, called Fuseproject, does innovative industrial design and branding while the second company, called Cionic, is from the medical device technology field. Vox is another low-cost, modular, and easy to use invention that runs on RaspberryPi single-board computer. Lung Evolve was designed by two Colombian teams from the National University in Bogota and Pontifical Bolivarian University in Medellin [9], (Fig. 6a). It features a cheap mechanical ventilator with a simple electrical and mechanical structure. It works based on the non-invasive conventional anesthesia model that is activated mechanically and controlled electronically. OP Vent was invented by a group of Californian inventors from Nvidia in Santa Clara, Waymo in Mountain View, Stanford University, and Veteran Affairs Health Care System from Palo Alto [10], (Fig. 6b). It is an open-source ventilator that uses a proportional solenoid valve, a microcontroller printed circuit board, and pneumatic systems to operate. RespiraWorks was built by a group of engineers, healthcare workers, and other professionals from across the world [11], (Fig. 7a). It uses a sophisticated ventilation system, open-source software, and a simple structure that is easy to manufacture and assemble.
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Fig. 5. CoVent-19 Finalists: a) Baxter Ventilator, b) CORE Vent, c) Vox (ex InVent)
Fig. 6. CoVent-19 Finalists: a) Lung Evolve, b) OP Vent
SmithVent was designed by a team of former graduates and friends from the Smith College in Northampton, Massachusetts, USA [12], (Fig. 6b).It is another solution that uses a pneumatic system, an easy-to-build enclosure, and a sophisticated control system.
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Fig. 7. CoVent-19 Finalists: a) RespiraWorld, b) SmithVent
2.4 Australia: 3D Printed ACTIVAT3D Copper Proven to Kill SARS-Cov-2 Virus on Contact Surfaces Australian company SPEE3D has developed and tested a fast and affordable method for 3D printing antimicrobial copper on the metallic surface [13], (Fig. 8). The laboratory tests have proved that the contact surface modified by this method kills up to 96% of the SARS-COV 2 - a virus that causes COVID-19 disease - in just two hours.The process, known as ACTIVAT3D copper, was developed by modifying SPEE3D the world’s leading 3D printing technology, using new algorithms to control their metal printers to allow coating of existing metal parts with copper. Copper parts are difficult to produce with traditional methods, so 3D printing is perhaps the only tool available for quick copper coating [14]. SPEE3D technology makes it fast and affordable. It has been demonstrated that copper quickly destroys bacteria, yeasts, and viruses by contact breaking cell walls and destroying the genome [13]. The SPEE3D team was able to coat the stainless steel door touch plate and other handles in just five minutes. Surfaces made of stainless steel and plastic can be disinfected but the problem with these surfaces is that, even with rigorous protocols, it is not possible to clean them constantly, according to SPEE3D. When surfaces become contaminated between cleanings, touching them can contribute to superspreading events. Touching of contaminated objects, known as fomite transmission, was suspected during the SARS-CoV-1 epidemic in 2003, and analysis of the nosocomial SARS57 CoV-1 superspreading event concluded that touching of contaminated objects (fomites) have a significant role in virus spreading. To confirm its ability to fight COVID-19, copper samples printed by SPEE3D have been tested in the laboratory and shown to kill SARS-CoV-2 [15]. Copper kills bacteria on contact by releasing ions that react with moisture and oxygen in bacteria to produce reactive oxygen, which destroys the bacteria cells and prevents mutation or passing the genes to the microbes by destroying bacteria’s DNA and RNA [16], (Fig. 9).
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Fig. 8. SPEE3D’s 3D printed ACTIVAT3D copper used on a door handle
1.
2.
3.
Fig. 9. SPEE3D’s explanation of how copper ‘contact kills’
2.5 Netherlands - Germany: Stepping up the Production of 3D Printed Anti-scatter Grids for CT Systems as a Way to Fight the COVID-19 CT imaging has become a valuable weapon in the war against the novel coronavirus, due to the possibility to detect the “ground glass” white spots in the lungs that are a sign of COVID-19 [17]. To support patient access to CT scans, Dunlee has increased the 3D printing of tungsten anti-scatter grids which are an important component of quality CT systems (Fig. 10). With only 100 µ thickness, Dunlee’s anti-scatter grid significantly improves CT images by absorbing scatter radiation that can degrade image quality. CT manufacturers need specialized components and materials to reach high levels of performance in their machines. One of the crucial components in CT scanners are antiscatter grids (ASG) used to absorb scattered radiation and enhance image quality [18]. The best material for these components is tungsten because of its resistance against high temperatures (3422 °C), its high resistance against wear, and the best performance in
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stopping radiation (Density: 19,3 g/cm3 ). However, because of the difficulty in processing tungsten and the demanding requirements for the use in medical devices, very precise and reliable manufacturing technology is needed. Additive manufacturing, specifically DMLS® Technology, has met the requirements to date; however, for mass adoption in the industry, these requirements are becoming more demanding concerning cost, quality, and performance. To solve this problem, AMCM, Dunlee, and EOS partnered to develop a customized EOS M 290 that prints with industry-leading 3D-printing resolution and accuracy to meet the demands of the reproducible quality of a 24/7 production.
Fig. 10. A CT-scatter-grid.
2D tungsten anti-scatter grids have great advantages compared with conventional 2D Molybdenum or 1D grids [19]. The high density of tungsten allows more X-ray scatter to be absorbed. Moreover, with the new design possibilities afforded by 3D printing, Xrays can now be directed into the photodiode more accurately. 3D printers that originally printed gold products are refurbished by EOS to increase capacity and made available to Dunlee for tungsten printing. In addition to anti-scatter grids, Dunlee also offers a broad portfolio of innovative components for CT systems.
3 Montenegrin 3D Printing Solutions Shortly after the outbreak of the COVID-19 pandemic in Montenegro, just similar to other countries,there was a need to deliver to medical facilities protective equipment
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whose supplies threatened to be depleted soon after the virus was imported into the country. Due to the pandemic, supply chains were having difficulties functioning, so the potential procurement of additional equipment could require a long wait period. Guided by a positive example of innovative responses to the growing needs of the health system, Montenegrin 3DP manufacturers in Montenegro have decided to join forces and start printing protective visors, masks, handle adapters and similarly to contribute to the community. In order to give their contribution, the Faculty of Electrical Engineering and Faculty of Mechanical Engineering at the University of Montenegro, Innovation and Entrepreneurship Center “Tehnopolis” from Niksic and Science and Technology Park Montenegro, with the support of the Ministry of Science, came up with the idea to use the capacities of 3D printers that were at disposal at the time and start printing certain segments of protective equipment and spare parts that were made available to the Institute of Public Health of Montenegro [20]. It was decided to start printing prototypes based on available 3D models: protective masks for respirators together with tubes, protective masks with HEPA filters, as well as protective visors. After the Institute of Public Health of Montenegro verified the quality and safety of the printed equipment, the cluster started its more intensive printing. Shortly afterwards, a number of other 3DP manufacturers joined the cluster, so that the 3D community that printed visors for the needs of the Montenegrin health system counted over fourty five 3D printers. The National Coordination Body for Infectious Diseases has decided that the Science and Technology Park Montenegro will be the main coordinator of 3D printing in order to centralize the entire system through one platform, and the supply process to run faster and without interruption. Also, noticing the efforts of the cluster, National Coordination Body
Fig. 11. 2D model of the thermal-sensor bracelet
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decided to provide financial assistance to the cluster for procurement of the necessary filaments, since due to the intensive use of available filaments, 3D producers soon ran out of their stock. To date, over 17000 protective visors have been delivered to the community, and the word is about over fifty different entities, primarily medical institutions. The most inovative solution that has been developed in Montenegro is the 3D printed bracelet that detects if a patient has a fever [21]. The bracelet is made of two materials: static PLA and tricolor adjustable PLA filament (Fig. 11) which are modeled in SolidWorks 2017 software. The bracelet is modeled in SolidWorks 2017 software and it’s body that wraps around the patient’s wrist is made out of static PLA while the central component (in the shape of Montenegrin map) is made out of tricolor adjustable PLA filament and it is the one changing color (Fig. 12). The bracelet is printed on a CraftBot Flow Idex XL double-headed 3D printer that can rotate parts using a printed shaft which allows the bracelet to wrap around the wrist. Using this double-headed printer enables making this bracelet in one piece. The model was sliced with a 0.4 mm nozzle and a 0.1 mm layer height using Craft Ware.
a)
b) Fig. 12. Colors of the bracelet when patients a)do not have a fever and b) with a fever
As it can be seen in Fig. 12 above, 3D printed medical equipment in form of a bracelet shows two different behaviors - when the temperature is below 37 °C, the central component remains gray (the filament that changes color is in one phase), but when the temperature rises above 37 °C, the filament goes to the second stage and it gets orange.
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4 Conclusion This paper deals with global and domestic 3D printing solutions which have proved to be more than efficient in the fight against the COVID-19 as a go-to method in case of medical supply shortages. Each country around the globe came up with different solutions. Montenegro is not different from them and through the support of Ministry of Science here is presented an efficient medical gadget which can help in controlling better Covid-19, since high temperature has shown to be on of the symptoms that appear more than often when people have the virus. A novel inovation gadget in the form of a bracelet with its characteristics has been presented in detail. Acknowledgments. This research was funded by the Ministry of Science in Montenegro, grant number 02/2-062/20-892/2, in the frame of project, “3D printing research and innovations Covid19”.
References 1. Coronavirus disease 2019, Wikipedia. https://en.wikipedia.org/wiki/Coronavirus_disease_ 2019 2. The latest 3D printing efforts against Covid-19, TCT. https://www.tctmagazine.com/additivemanufacturing-3d-printing-news/live-blog-how-the-3d-printing-industry-fighting-covid-19/ 3. Farsoon and Partners share additive manufactured Covid-19 fighting tools, Farsoon. https:// en.farsoon.com/yl_detail/productId=98.html 4. EASY COVID 19, Isinnova. https://www.isinnova.it/easy-covid19-eng/ 5. INNOVATE2VENTILATE, CoVentChallenge. https://www.coventchallenge.com/ 6. Baxter Ventilator, GrabCAD. https://grabcad.com/library/baxter-ventilator-1 7. CORE Vent, GrabCAD. https://grabcad.com/library/core-vent-1 8. InVent Pneumatic Ventilator, GrabCAD. https://grabcad.com/library/invent-pneumatic-ventil ator-1 9. Lung Evolve, GrabCAD. https://grabcad.com/library/lung-evolve-1 10. OP Vent, GrabCAD. https://grabcad.com/library/op-vent-1 11. RespiraWorks, GrabCAD. https://grabcad.com/library/respiraworks-1 12. SmithVent, GrabCAD. https://grabcad.com/library/smithvent-1 13. 3D printing copper on surfaces can kill COVID-19 virus, 3D natives. https://www.3dnatives. com/en/copper-covid-19-250420204/#! 14. 3D Printed ACTIVAT3D Copper Proven to Kill SARS-Cov-2 Virus on Contact Surfaces, PR Newswire. https://www.prnewswire.com/news-releases/3d-printed-activat3d-copper-pro ven-to-kill-sars-cov-2-virus-on-contact-surfaces-301040163.html 15. 3D Printed Copper Proven to Kill SARS-CoV-2 Virus on Contact Surfaces, Digital Engineering 24/7. https://www.digitalengineering247.com/article/3d-printed-copper-proven-tokill-sars-cov-2-virus-on-contact-surfaces/ 16. 3D printing a metallic coating of antimicrobial copper to fight the spread of COVID-19, SPEE3D. https://spee3d.com/activat3d-copper/ 17. Altunbas, C., Kavanagh, B., Alexeev, T., Miften, M.: Transmission characteristics of a twodimensional anti-scatter grid prototype for CBCT. Med. Phys. 44(8), 3952–3964 (2017) 18. Printing Anti-Scatter Grids for CT Scanners, AMCM. https://amcm.com/success-stories/pri nting-anti-scatter-grids-for-ct-scanners-on-amcm-systems
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19. EOS and Dunlee joined forces to ramp up anti-scatter grid production in response to the novel coronavirus, 3D Printing Media Network. https://www.3dprintingmedia.network/eosand-dunlee-joined-forces-to-ramp-up-anti-scatter-grid-production-in-response-to-the-novelcoronavirus/ 20. Science and Technology Park Montenegro. https://www.ntpark.me/en/2020/05/14/3d-pri nting-vs-coronavirus 21. Ðukanovi´c, M., Mavri´c, A., Jovanovi´c, J., Roganovi´c, M., Boškovi´c, V.: Design of 3D printing thermo-sensored medical gear in detecting COVID-19 symptoms. MDPI Appl. Sci. 10, 10–11 (2020)
Measurement of NACA Airfoil Characteristic Parameters on 3D Printed Models Kenan Varda, Ernad Bešlagi´c, and Nermina Zaimovi´c-Uzunovi´c(B) Mechanical Engineering Faculty, University of Zenica, Zenica, Bosnia and Herzegovina [email protected]
Abstract. Engineering measurement of complex geometrical models shapes, is done by using unconventional measurement equipment rapidly developed in recent time. Coordinate measuring machines are widely used for this purpose, but CMM have certain limitations which are reflected in the impossibility of positioning models of complex shapes and materials, as well as the precision of registrating coordinates on such models. So, 3D scanners are also appropriate tools for complex shape model measurements. This paper presents the process of making NACA 4415 model using 3D printers, Ultimaker S5and Formlabs Form 3. Real, 3D printed complex models, are scanned using 3D scanner Range Vision Pro and its software. Authentic 3D CAD NACA models type of airfoil are created for the purpose of measurement of characteristic parameters defined by the standard. GOM Inspect software enable a comparison of nominal CAD models with scanned object models created on the above-mentioned printers. The results of comparisons are shown in the paper conclusions as the numerical values of geometrical parameters between scanned models performed on different printers. Keywords: Airfoil · NACA · Measurement · Geometry deviation · Metrology
1 Introduction The wind turbine rotor is the first element in the system by which wind energy is converted into electricity. aerodynamic and dynamic properties of turbine rotor have a multiple influence on the entire wind turbine system. The rotor ability to convert the maximum amount of wind energy which passing through the rotor into mechanical energy is a direct result of aerodynamic properties and mostly determine the overall efficiency of the entire wind turbine. The rotor aerodynamic properties are mostly determined by the aerodynamic properties of used airfoils. Therefore, the correct choice of airfoil is very important from performance and production of blades point of view. In addition, certain characteristics of the airfoil are important for the control, operational behaviour and rotor efficiency. This primarily refers to the occurrence of a sudden decrease in buoyancy force when the airfoil exceeds the critical attack angle. Since the rotor blades in certain operating conditions inevitably pass into the ranges of attack © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 323–332, 2021. https://doi.org/10.1007/978-3-030-75275-0_36
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angles at which the air flow separates from the blades, it is important to choose an airfoil that reduces the unwanted consequences of this phenomena. Although there are a large number of different airfoils, the basic geometric parameters are common for each of them. The main curve line or the camber line is the line that connects the points located in the middle between the upper and lower surface of the profile. The most protruding points of the centre line are called the leading and trailing edges of the profile. The straight line joining the leading and trailing edges of the airfoil is the midline tendon and its length is denoted as the profile tendon c - chord. Profile curvature - camber is the distance between the main curvature line and the tendon line, measured perpendicular to the tendon. The thickness of the profile is the distance between the upper and lower surface, also measured perpendicular to the tendon line. The attack angle α is the angle between the direction of the resulting air flow velocity around the blade vr and the chord. The geometrical parameters that have the greatest influence on the aerodynamic performance of the airfoil are: the radius of the leading edge of the profile r LE , camber line, the maximum thickness t and the thickness distribution along the profile. Therefore, during the production of the profile, it is very important to achieve the required values of the specified geometric parameters of the airfoil. The first systematically developed airfoils were used for aircraft wings and were created in the period from 1923–1927 at the Development Institute for Aerodynamics in Germany (Aerodynamische Versuchsanstalt in Göttingen). These airfoils have been replaced by airfoils from the NACA (National Advisory Committee for Aeronautics) series. The NACA airfoils were designed during the period from 1929 through 1947 under the direction of Eastman Jacobs at the NACA’s Langley Field Laboratory. Most of the airfoils were based on simple geometrical descriptions of the section shape, although the 6 and 6A series were developed using theoretical analysis and don’t have simple shape definitions. Although a new generation of airfoils has emerged as a result of improved understanding of airfoil performance and the ability to design new airfoils using computer methods, the NACA airfoils are still useful in many aerodynamic design applications. The shape of the NACA airfoils is described using a series of digits following the word “NACA”. These multi-digit marks contain information of the airfoil geometry and, in some part, on certain aerodynamic properties. The parameters in the numerical code can be entered into equations to precisely generate the cross-section of the airfoil and calculate its properties. The most famous families of airfoils are marked with four, five and six digits, or more precisely, the marks. Each label in the NACA profile name has its own meaning. Between these six series, the simplest to define are the NACA airfoils of the fourth series, ie. those which have the four-digit mark. The numbering system for these airfoils is defined by: NACA MPXX where: XX is the maximum thickness, t/c, in percent chord, M is the maximum value of the mean line in hundredths of chord and P is the chordwise position of the maximum camber in tenths of the chord. Four-digit series airfoils by default have maximum thickness at 30% of the chord (0.3 chords) from the leading edge.
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Fig. 1. Geometric parameters of NACA 4415 airfoil
For the purposes of this work, a segment of the Darrieus vertical axis wind turbine blade was modelled and manufactured. The air profile of this blade is NACA 4415 while the chord length is c = 60 mm. The equations that define the final coordinates for the airfoil upper and lower surfaces are given in [1]. Figure 1 shows the geometric parameters of the specified airfoil which values were later controlled, while Table 1 shows the nominal numeric values of these parameters. Table 1. Geometric parameters of NACA 4415 airfoil (M = 4, P = 4, XX = 15), chord length 60 mm Name
Mark
Expression
Value [mm]
Chord
c
–
60
Maximum thickness
t
XX·c/100 = 15·60/100
9
Chordwise position of the maximum thickness
xt
30·c/100 = 30·60/100
18
Maximum camber
m
M·c/100 = 4·60/100
2,4
Chordwise position of the maximum camber
xm
P·c/10 = 4·60/10
24
Leading edge radius
r LE
1,1019·t 2 /c = 1,1019·92 /60
1,4692
2 Models Production Using Additive Tehniques of 3D Printing The first step in the process of controlling shape and dimension deviations is to create realistic models, using 3D printers; Ultimaker S5 and Formlabs Form 3. Knowing the fact that the technology used by these printers is different, it is easier to determine the advantages and disadvantages of using one or another printer in reverse engineering. The Ultimaker S5 is a professional 3D printer, which owns open filament system – print with any 2,85 mm material, large build volume: 330 × 240 × 300 mm and down to 20 µ layer resolution. It uses fused filament fabrication printing technology with
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dual extrusion print head with an auto-nozzle lifting system, swappable print cores and dual-geared feeder, reinforced for composite materials [2]. On the other side, Formlabs Form 3 is professional stereolithography or resin printing 3D printer, which has custom-designed Light Processing Unit (LPU) inside itself and uses a compact system of lenses and mirrors. Formlabs Form 3 has a high-power-density laser that passes through a spatial filter to guarantee a clean laser spot. A parabolic mirror ensures that the laser prints perpendicular to the build plane, ensuring uniform print quality across the entire build platform [3]. Table 2. Printing parameters for both printers Ultimaker S5
Formlabs Form 3
Material
PLA
Resin
Material
Layer height
0,2 mm
25 µm
Resolution
Line width
0,35 mm
250 mW
Laser power
Wall thickness
1,05 mm
1,00
Density
Infill density
35%
0,5 mm
Touchpoint size
Printing temperature
210 °C
0,1 mm
Layer thickness
Print speed
25 mm/s
33,86 ml
Resin volume
Using the standard dimensions generated for the NACA 4415 airfoil on the NACA platform, a point cloud with coordinates was created and imported into CAD 3D modeling software, SolidWorks, and a nominal CAD model was created. In addition to the extruded CAD model of the airfoil, an airfoil stand was created, which makes the printing and positioning of models on printers easier, and at a later stage, scanning of the real models. For both 3D printers, the optimal printing parameters were set, shown in Table 2.
Fig. 2. Preparation for printing on Ultimaker (left) and Formlabs (right)
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Fig. 3. Real printed models (left Ultimaker, right Formlabs)
One of the most important things in the process of preparation for printing is the positioning of the model itself. The most ideal positions for printing were selected, which reduce the maximum amount of supports that are required when making a printed model, which is shown in Fig. 2.
3 Real Models 3D Scanning The process of scanning and creating 3D scanned models on the RangeVision Pro 3D scanner begins with selecting the appropriate lenses for scanning models of certain dimensions. The RangeVision scanner has three sets of lenses, which are intended for scanning models of different dimensions. In the specific case, for the model that was printed for this work and whose largest dimension is 60 mm, a set of lenses marked with the number 3 was chosen, it is used for objects whose maximum dimensions are in a range between 50 to 150 mm. When setting up lenses on a 3D scanner, it is important to calibrate the new lenses. This step is crucial for defining the main parameters of the scanner and lenses, as well as for the table that is located within the scanner and serves as a basis for models while scanning. The process of calibrating the scanner passes a series of 11 steps, where the reference plate, which has certain predefined markers, is positioned in several ways and also, the light, brightness and exposure of the projector itself are adjusted [4]. The scanning begins with table axis evaluation, because the scan was performed on the rotary table of the scanner, whose coordinate system is important to be determined before the scanning, so that the scans can be linked into the final model. Without axis evaluation, there is dispersion of scans [5]. In the scanner options, automatic brightness and exposure were selected, the number of table movements was defined, respectively the 16 number of shots per pass. For each of the models, three groups of scans were made. The models made on Ultimaker and Formlabs were scanned into three groups of scans with 16 images each and the models were positioned in that way that all views of the model were included. When scans were made, it was necessary to align those three groups of scans, position them in space and do global registration of scans. Scans are presented in Fig. 4 for Ultimaker and Fig. 5 for Formlabs. During the processing, scans were also cleaned of possible unwanted scanned details from the environment. In addition, before creating the 3D model itself, the holes were
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Fig. 4. Ultimaker scans
Fig. 5. Formlabs scans
filled with an tool, which works on the principle of approximation between the nearest neighbouring points. The final step was to create a 3D model. The model was exported to the universal.STL format, which was later used to control the dimensions of the airfoil (Fig. 6).
4 Airfoil Parameters Control Using GOM Inspect Software GOM Inspect is a software for analysing 3D measuring data from fringe projection or laser scanners, coordinate measurement machines (CMM) and other measuring systems. The GOM software is widely used in shape and position control, surface deviations and dimensions control.
Fig. 6. 3D models in universal.STL format (left Ultimaker, right Formlabs)
4.1 Alignment In particular case, surface and line profile, as well as airfoil parameters were controlled with GOM Inspect software. It was CAD and scanned models comparison proceeded. In process of GD&T (shape and position) control using GOM, we used nominal CAD model created in the CAD software, and actual meshed model created by 3D scanner [6]. First step in GOM inspection was to align CAD and Meshed models. This is done by using Prealigment tool, and actual scanned model was aligned with CAD nominal
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model (Fig. 7). In the Ultimaker case, nominal CAD model was painted green and Meshed model was painted red. Analog to that, in Formlabs case, nominal CAD model was painted purple, and Meshed model was painted yellow.
Fig. 7. CAD and Meshed models aligned (left Ultimaker, right Formlabs)
4.2 Creating Sections and Surfaces for Controlling For purpose of this work, four parallel sections on nominal and actual models were created. Positioned in such way, perpendicular to Z axis, every section intersected each (CAD and Mesh) model and created profile contour which is copied to each section. Every of these eight contours (four on CAD model and four on Mesh) were controlled. Every section was created on different height. First section was created at 7 mm hight, after that, every next section is created higher for 13 mm, on 20, 33 and 46 mm. For surface profile deviation control, it was necessary to create to surfaces on meshed model (Fig. 8).
Fig. 8. Sections created on Meshed models (left Ultimaker, right Formlabs)
4.3 Performing GD&T Control on Surface and Line Profiles For GD&T (shape and position) control, actual model and section were used. On actual model, external surface of airfoil was selected as surface for controlling. This surface
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on actual model was compared with the same surface on nominal model. Analog to this procedure, for each line profile created on parallel sections on actual model, comparison was performed and controlled with corresponding line profile (Fig. 9). Surface profile deviation and line profile deviation were calculated and presented in the Table 3.
Fig. 9. Surface profile and line profile deviation
Table 3. Surface and line profiles deviations (LD) on actual meshed model Measured parameters
Surface deviation
Max. LD on 7 mm
Max. LD on 20 mm
Max. LD on 33 mm
Max. LD on 46 mm
Ultimaker
0,58 mm
0,48 mm
0,23 mm
0,21 mm
0,24 mm
Formlabs
0,55 mm
0,20 mm
0,15 mm
0,16 mm
0,16 mm
4.4 Airfoil Characteristic Parameters Analysing GOM Inspect software gives a few special tools, recommended for airfoil analysis. In the menu Inspection, under Analyze Airfoil, few tools were used for airfoil parameters control: Camber line, Profile Chord Line, Profile Edge Circles and Max. Thickness. On each of eight sections on both actual models (Ultimaker and Formlabs), airfoil profiles were created and, in this step, used for control. It is possible to represent these characteristic parameters visually and write in tables on screen (Fig. 10). In GOM Inspection software, few standard parameters for NACA 4415 can’t be calculated, otherwise, these which were calculated were presented and compared with nominal values in the Tables 4 and 5.
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Fig. 10. Visual representation of airfoil parameters values
Table 4. Controlled parameters on Ultimaker actual airfoil and measured values Ultimaker actual airfoil profile Parameter
Actual-20 mm
Actual-33 mm
Actual-46 mm
Nominal
Chord length 59,63 mm
Actual-7 mm
59,49 mm
59,50 mm
59,50 mm
60 mm
Maximum thickness
9,62 mm
9,50 mm
9,45 mm
9,43 mm
9 mm
Leading edge 2,16 mm radius
1,91 mm
1,85 mm
1,85 mm
1,4692 mm
Distance x t
18,52 mm
17,75 mm
18,27 mm
18 mm
17,84 mm
Table 5. Controlled parameters on Formlabs actual airfoil and measured values Formlabs actual airfoil profile Parameter
Actual-7 mm
Actual-20 mm
Actual-33 mm
Actual-46 mm
Nominal
Chord length 59,78 mm
59,83 mm
59,82 mm
59,94 mm
60 mm
Maximum thickness
9,37 mm
9,35 mm
9,36 mm
9,37 mm
9 mm
Leading edge 1,84 mm radius
1,79 mm
1,84 mm
1,82 mm
1,4692 mm
Distance x t
17,06 mm
18,23 mm
19,10 mm
18 mm
18,15 mm
5 Conclusion This paper clearly shows that additive techniques of 3D printing are very applicable for producing variant solutions of products that need to be modified in process of experimental examinations, as well as in process of choosing the best solutions. Furthermore, it is obvious that products made on modern professional 3D printer will be used as finished products in the future in many industries such as engineering and medicine.
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Also, during the process of 3D scanning of a known dimensions and geometry objects, it was noticed that precise and purity of scans are very high and such scanners as RangeVision Pro could be used for scanning of fine machine elements. In the postprocessing, GOM Inspect software was very useful for measurement and determine shape and position deviations on scanned model. In particular case, characteristic parameters of NACA 4415 airfoil were measured and results present that maximal surface deviation on scanned model is 0,58 mm, and maximal dimension deviation is 1,1 mm. Knowing a fact that 3D printing techniques are not very precise and reliable in producing of very accurate models, these results are respectable. Some future papers will try to determine factors that are mostly enter the error in process measurement of 3D printed models and their scans.
References 1. Abbott, I.H., Von Doenhoff, A.E.: Theory of Wing Sections: Including a Summary of Airfoil Data. Dover Publications, Inc., New York (1959) 2. https://ultimaker.com/3d-printers/ultimaker-s5 3. https://formlabs.com/3d-printers/form-3/ 4. Bešlagi´c, E., Spahi´c, D., Kaˇcmarˇcik, J., Petkovi´c, D.: Reverzni inženjering kompleksne geometrije na osnovu skeniranog modela. In: Proceedings of the QUALITY 2019, Neum, B&H, 14–16 June 2019, pp. 275–280 (2019). ISSN 1512-9268 5. https://rangevision.com/en/products/pro/ 6. https://www.gom.com/3d-software/gom-inspect.html
Analysis and Improvement of Industrial Production Lines Assisted by 3D Printing Erald Piperi(B) , Ilo Bodi, Dea Sinoimeri, Tatjana Spahiu, and Jorgaq Kaçani Mechanical Engineering Faculty, Polytechnic University of Tirana, Tiranë, Albania [email protected]
Abstract. Product quality as well as product performance, plays a significant role in client satisfaction. Production line managers are interested in increasing productivity through implementing new strategies and improving the traditional way of production. Based in internal audit claims for non-conformity products, it was found that the operators didn’t understood the mounting process. This paper analyzes and shows a practical case how assembly production lines, in a manufacturing company in Albania, benefitted from advanced technologies as 3D printing. The 3D printed parts, implemented in the production line based in Poka-Yoke solution, has helped overcoming claims related to montage in wrong positions, length error and incorrect orientation of the products. Keywords: 3D printing · Assembly lines · Increased productivity · Poka-Yoke
1 Introduction Product quality is a major concern in today’s modern production systems. Poor quality products decrease customer satisfaction, reduce efficiency, and increase the cost of business operation. It is important to dig out the root causes and eliminate the variance in the production line [1, 2]. The traditional way of solving assembly and maintenance problems is to spend a lot of time and money for training and instructing workers what not to do. But when people leave the company, they take their experience and knowledge with them and the assembly difficulties stay behind. One way to find clues for solving assembly problems comes from examining their source and spotting the trouble ahead of time [3]. Poka-yokeas a quality assurance technique developed by Japanese manufacturing engineer Shigeo Shingo comes from the Japanese words ‘poka’ (inadvertent mistake) and ‘yoke’ (prevent). It deals with “fail-safing” or “mistake-proofing” [4]. Poka-yoke is also an essential process component of Motorola’s Six Sigma strategy [5, 6]. It is started in Japanese organisations to implement a zero quality control (ZQC). One of the elements of implementing the principle of ZQC is the Poka-yoke method [7–9]. As an innovative technique for preventing human error at work, these technique starts by analysing the process for potential problems, categorising parts by the characteristics of dimension, shape & size & weight, detecting process deviation from nominal procedures and norms [10]. Low cost automation and Poka-yoke philosophy assure good results when applied to manufacturing processes with a high incidence of human © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 333–340, 2021. https://doi.org/10.1007/978-3-030-75275-0_37
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operators, with a low availability of time for solution implementation and with expensive effects associated with errors in executing operative procedures [11]. The paper is intended to focus basic concept of achieve a high performance of productivity with implementation of Poka-yoke mechanism. It covers a practical study work implemented in Forschner company in Albania. The final solution was the well designed of diferents counterparts with the intent of eleminating different problems related to length error, incorrect position and orientation of the mounting cable ties. The 3D printing technology helped the company to bypass these obstacles within a shorter time and cost eficiency.
2 Poka-Yoke Poka-Yoke is a continual improvement strategy that offers a way to move the QMS (Quality Management System) towards a higher level of performance [11, 12]. The Poka-Yoke concept was generated in the middle of 1950’s by Shigeo Shingo, who is Japanese industrial engineer. Shingo was working for the Toyota, where he developed entire Manufacturing systems focused on achieving zero defects in production and gave birth to this revolutionary work. To stay in market and to become a whole world-class competitor, a company must go with new strategy and technology along with side by side practice of producing zero defects [13]. 2.1 Problem Identification In the 1960’s, Forschner company began with the production of electromechanical components and this followed about thirty yearslater by cabling systems and on-board wiring systems for commercial vehicles.This diversification, combined with entry into new product sectors, created the basis for sustainable growth.Forschner is well-known for: loyalty, respect, team spirit, ambition, discipline and openness [14]. In this paper, the company had a claim from a client for non-mountable cable harness due to incorrect orientation of the mounting cable ties (Fig. 1). 8D methodology was used to overcome this claim in the assembly line. 2.2 8D Methodology ‘8D’ is a systematic tool or method for solving claim or problem with ‘8 steps’ or ‘8 disciplines’ The purpose of 8D methodology is rapid, lasting and systematic processing of claims, identifying and eliminating the root cause. It enables transfer of lessons learned to similar processes and product and helps in continuous and complete documentation of the problem solving process [15]. D1 THE PROBLEM SOLVING TEAM IS FORMED Name, Dept. (Depmt) - For solving this problem, 3 people was part of this methodology. Team Leader (Champ.) - Eva Sherri.
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Fig. 1. Non-mountable cable harness due to incorrect orientation of the mounting cable ties (problem of the claim)
D2 PROBLEM DESCRIPTION (Problem Description) - KB67 Cable tie 4.6 × 200 T50R (sheet metal) mounted on the wrong side. (Problem Profile Data) - Production error D3 CONTAINMENT ACTIONS – – – – – –
Informed the engineer and production for the importance of the claim. Controlled the drawing documentation. Controlled the forming board. Controlled the stock in production. Controlled the stock in Warehouse AL. Controlled the stock in Central Warehouse CZ.
D4 ROOT CAUSE ANALYSIS Analysed the problem and came to conclusion that: – The error has occurred during the forming phase of the harness on the forming board. – The operator hasn’t understood the drawing documentation and the montage of the KB67 was done on reverse. – New operator - training has not been efficient. – No first release was done in the working place. – No available visualization of the KB67/3D counterpart on the forming board. Due to the above-mentioned reasons we accept this problem. D5 CORRECTIVE ACTIONS AND PROOF OF EFFECTIVENESS – Re-training of the operator in accordance with training manual AA-AL-001i Training Manual.
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– Montage of the 3D counterpart on the forming board - this action will run as a Poka-yoke solution - clear visualization for the operator to mount the KB 100% in accordance with the drawing documentation. – Definition of other cables and forming boards that may be affected from the same error - implementation of the action also on similar cables. D6 INTRODUCTION OF CORRECTIVE ACTIONS AND TRACKING OF EFFECTIVENESS – Re-trained the operator in accordance with training manual AA-AL-001i Training Manual. – Montage of the 3D counterpart on the forming board - this action will run as a Poka-yoke solution - clear visualization for the operator to mount the KB 100% in accordance with the drawing documentation. – Definition of other cables and forming boards that may be affected from the same error - implementation of the action also on similar cables. D7 PREVENTION OF RECURRENCE OF THE NON-CONFORMITY Table 1. Prevention of the recurrence of the non-conformity Implementation in:
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Product FMEA
+
Process FMEA
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Control plan
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Procedure
D8 FINAL MEETING Due to the hardwork of the team dedicated to this company claim, everything ended successfully. 2.3 Proposed Solutions In order to prevent the occurrence of defect in the claim (Fig. 2), the following solutions were proposed by the team: – Re-training of the operator in accordance with training manual AA-AL-001i Training Manual. – Montage of the 3D counterpart on the forming board - this action will run as a Poka-yoke solution - clear visualization for the operator to mount the KB 100% in accordance with the drawing documentation. – Definition of other cables and forming boards that may be affected from the same error - implementation of the action also on similar cables.
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Fig. 2. After installation, the cable is stuck on the edge (problem of the claim)
2.4 Results The impact of implementation of Poka-yoke mechanism and the mounting of the 3D printed counterpart showed in (Fig. 3) can be described as follows: – Indicates the operator to mount the required cable tie/clip/mounting base. – Prevents the montage in wrong orientation. – Prevents length errors.
Fig. 3. During implementation of Poka-yoke (solving the problem of the claim)
Benefits for applying Poka-yoke (except the quality of what is produced), are as follows: – Workers will need less training, because the process they following will automatically correct any deviation from what is required. – Increased safety where work is done with hazardous materials or in risky conditions, such as working with electricity or petrochemicals. – Quality checks by sampling and inspection can be reduced, because the elimination of mistakes is built into the process, either by prediction or by detection
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– The work will be less repetitive and boring because of the removal of some of the inspection that was needed before. – Quality-based work and continuous improvement become a way of life. – No defective items, or very few, are produced, thus reducing waste and costs.
Fig. 4. Prevention of recurrence of the non-conformity of Poka-yoke
Studying the total overview of claims received in the timeline of the years 2018–2020 in the Forschner company, for the following issues: - Missing cable tie/clip/mounting base - Incorrect montage (orientation or position) of the cable tie/clip/mounting base - Incorrect distance of the cable tie/clip/mounting base the impact of corrective actions (8D Methodology and Poka-yoke) is absolutely excellent (2018 – 14 claims; 2019 – 5 claims; 2020 – 0 claim) (Fig. 5).
Fig. 5. The impact of corrective action in the timeline 2018–2020
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3 Conclusion This paper deals with two problems, a) quality improvement through Poka-yoke and 8D methodologyfor problem aproach and b) design and production throw 3D printing technology of different parts helping operators to eleminate obstacles and mistakes efectively. Poka-yoke is an essential process component of Forschner company strategy.The aim of Poka-yoke strategy is to eliminate or to minimise human errors in manufacturing processes and management, as a result of mental and physical human imperfections. Errors arise from various reasons, but most of them can be prevented if only people are able to identify the problem at the time of formation, define the causes and make appropriate corrective steps. Prevention of defects in the process before their appearance is the best way of defects reduction and thus reduces the pruduction costs. 8D Methodology is effective in solving problems in an assembly line. Zero defects are achieved with the implementation of Poka-yoke system assisted by advanced techonolgy as 3D printing to shorter production time and cost effectiveness. Acknowledgements. The authors would like to express their gratitude to the Forschner Albania sh.p.k. Company and to all their staff members for making these work possible throw extensive collaboration and positive impact in establishing new technologies aproaches as 3D printing in Albania.
References 1. Tsou, J.-C., Chen, J.-M.: Dynamic model for a defective production system with Poka-yoke. J. Oper. Res. Soc. 56(7), 799–803 (2005) 2. Klug, F.: Failure-tolerant logistics processes based on Poka-yoke. Prod. Manage. 15(3), 20–23 (2010) 3. Dvorak, P.: Poka-yoke designs make assemblies mistake-proof. Mach. Des. 70(4), 181–184 (1998) 4. Robinson, H.: Using Poka-yoke techniques for early defect detection. In: 6th International Conference on Software Testing Analysis and Review (1997) 5. Smith, B.: Making war on defects: six-sigma design. IEEE Spectr. 30(9), 43–47 (1993) 6. Evans, J.R., Lindsay, W.M.: Managing for Quality and Performance Excellence. Thomson Higher Education, Ohio, USA (2008) 7. Shingo, S.: Zero Quality Control Source Inspection and the Poka-Yoke System. Productivity Press, Potland (1986) 8. Fisher, M.: Process improvement by Poka-yoke. Work Study 48(7), 264–266 (1999) 9. Ketola, J., Roberts, K.: Demystifying ISO 9001:2000 – part 2. Qual. Prog. 34(10), 44–47 (2001) 10. Patel, S., Dale, B.G., Shaw, P.: Set-up time reduction and mistake proofing methods: an examination in precision component manufacturing. TQM Mag. 13(3), 175–179 (2001) 11. Gebennini, R., Rimini, E., Spadaccini, B., Gamberini, E., Zilocchi, D.: Low cost automation and Poka-yoke devices: tools for optimizing production processes. J. Prod. Qual. Manage. 4(5–6), 590–612 (2009) 12. Bandyopadhyay, J.K., Amilinine, L.: Developing a model for quality management program in an American University in this new millennium. Int. J. Qual. Prod. Manage. 4(1), 1–8 (2004)
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13. Shingo, S.: A Study of the Toyota Production System. Productivity Press (1981) 14. Forschner (2021). https://www.forschner.com/en/forschner 15. Rambaud, L.: 8D Structured Problem Solving: A Guide to Creating High Quality 8D Reports. Phred Solutions, Breckenridge, USA (2006)
Experimental-Numerical Analysis of Hot Forging Process with Monitoring of Heat Effects Marko Popovi´c, Vesna Mandi´c(B) , Marko Deli´c, and Vladimir Pavi´cevi´c Faculty of Engineering, University of Kragujevac, Kragujevac, Serbia [email protected]
Abstract. The paper deals with the experimental-numerical analysis of the hot forging process on a hammer, where the main focus is on monitoring the thermal effects that occur in this metal forming technology. This includes measuring and numerically estimating the temperature fields in the workpiece and forging tools in multi-stage forging process. For this purpose, a thermal imaging camera for measuring the temperature in the industrial process and Simufact.forming software for numerical modelling of the process using the finite volume method were used. The results presented in the paper show that the complementary application of numerical simulations and industrial measurements enables the identification of thermal effects on both, workpiece and tools, in the entire technological process of multi-stage forging, through precise determination of input parameters for numerical simulations by infrared thermography. Keywords: Numerical simulation · Forging · Infrared thermography · Temperature fields
1 Introduction Virtual manufacturing (VM) technologies have proven to be very useful in meeting the increasingly stringent requirements imposed by modern industry on companies. Their application can greatly reduce the time of product development, while reducing costs and preventing the occurrence of defects and failures in production. Virtual models of technological processes enable the investigation of the impact of design changes on product quality, which contributes to the optimal use of production equipment and tools. VM technologies help engineers make decisions, by simulating various engineering activities, which can eliminate expensive physical prototypes and experiments [1, 2]. Today, a large number of papers can be found in the literature, whose authors used the FE/FV (Finite Element/Finite Volume) numerical simulation to analyze various influential parameters in the forging process. Mandic et al. (2014) in their work used modern virtual engineering technologies for the development of artificial hip forging technology. Using reverse engineering technology, a CAD model of forging tools was developed which was then used for numerical simulations. The results of those numerical simulations enabled better quality of production and analysis of all important parameters that affect the forging process in a significantly shorter time and with lower costs compared © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 341–349, 2021. https://doi.org/10.1007/978-3-030-75275-0_38
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to the traditional approach [3]. In paper [4], the authors analyzed the material flow state, strain and temperature fields, and the obtained results of numerical simulation provided useful guidelines for optimal performance of the forging process, tool design and material selection. Movrin et al. (2010) analyzed the relevant parameters that affect forging quality and stress reduction during the process, and verified the numerical simulations in a real industrial environment [5]. Infrared thermography is used, among other approaches, to identify the parameters used in the mathematical modelling of thermal phenomena in the simulation of the forging process. Cancelos et al. (2016) used IR thermography to develop a thermomechanical model to describe the forging process. The model was implemented in software for numerical process simulation, which estimates the thermal stresses and flow stresses in the material and tools during hammer impact, and the numerical results showed quite good agreement with the results of experimental measurements [6]. To accurately determine the input parameters for numerical process simulation, a series of experimental tests must also be performed. The results of experimental research presented in [7] show that IR thermography is suitable for precise measurement of the temperature fields during the forging process, and the results obtained by IR thermography deviated very little from the results obtained by thermocouples. Usamentiaga et al. (2014) describe IR thermography as an efficient technology for temperature measurement and non-destructive testing, and also point to various limitations and problems that must be taken into account [8]. Thajeel (2013) finds that this non-contact method provides safe temperature measurement without any possibility of degradation on the examined objects. The author states that parameters such as emissivity coefficient, complexity of geometry and surface reflection have a great influence on the measurement results [9]. The aim of this paper is to compare experimental and numerical analysis of thermal effects in hot forging on hammers, using Fluke Ti400 thermal imaging camera and Simufact.forming software for numerical process simulation, to prove the consistency of both approaches and the need for their complementary application for reliability of simulation results. This enables precise determination of complete temperature fields over the entire volume of the workpiece and tools and not only on visible surfaces for the IR camera. The elements that were the subject of the temperature measurement by IR thermography were dies, tool cavities, billet, workpiece and finish forging. IR images obtained with a thermal imaging camera used in industrial process were processed outside the production environment. Through comparison with the results of numerical simulation of the forging process, fine adjustment of process input parameters for mathematical description of thermal processes was performed, in order to implement a complete analysis of multi-hammer forging process, starting from billet heating, three forging operations, inter-operation cooling, transport and forging disposal.
2 Numerical Simulation of the Hammer Forging Process The finite volume (FV ) method is used to simulate the hot forging process, which belongs to the volumetric forming processes in the hot state. The FV method is based on dividing the domain Ω into a finite number of subdomains Ω i . Simufact.forming software uses
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an explicit MSC Dytran solver [10, 11].The material flow simulation is done based on the fixed grid called the Finite Volume Mesh where its elements are aligned with the coordinate system axes. The outer surface of the workpiece is meshed with triangular facets. In this approach there is only a need for “remeshing” of the outer surface of the workpiece, not the internals. This makes the FV solver uniquely suited for 3D hot forging process with complex die geometry and forgings. The process of forging a fork on a hammer consists of three operations: preparatory, preform and finisher forging. The industrial tool has two cavities made so that the first two operations are realized in one and the finisher forging operation in the other. Figure 1 shows CAD models of moulds and photographs of industrial tools. The tools are mounted on a Forging hammer Huta Zygmunt MPM2000. The mass of the falling parts is 2.5 t.
Fig 1. CAD models and photos of forging molds (left - lower mold, right - upper mold)
The billet measuring Φ 70 × 92 mm is made of C45E steel. The flow curves for this material were taken from the material database of Simufact software, which were determined at elevated temperatures corresponding to the simulation of the forging process. The initial mesh of final volumes on the billet was 3.2 mm and generated with the option of remeshing included during the simulation. When defining the characteristics of the workpiece material for numerical simulation, it is necessary, in addition to the flow curves and data on thermal conductivity and specific heat capacity, to define other coefficients describing thermal processes in the solver. Since the temperature fields in the tools, i.e. the cavities of the forging moulds, are also monitored, the coefficients are defined which describe the thermal processes in the tool material H13. Table 1 provides those data for workpiece and tool materials used in the numerical simulation.Contact friction in the forging process is described by a model of constant friction with a factor m = 0.6. The geometric parameters of the forging process are set for numerical simulation as shown in Fig. 2. The temperature fields in the billet, obtained by numerical simulation of the forging process, are shown in Fig. 3, at the time of heating in an induction furnace to the forging temperature(1170 °C), then after 3 s of cooling during transfer to the hammer, after the first hammer blowin preparatory forging, after the second hammer blow, then in the phase of preform forging, and finally after the finisher forging operation. Based on the recording of the entire forging process by used IR camera, the time durations of all phases in the technological process were known, and used in numerical process simulation. The cooling of fork forging after the forging process was also recorded, so additional simulations of cooling of the finish forging were realized, in the duration of
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Workpiece
Dies
Workpiece temperature
1170 °C
Heat transfer coefficient to environment
50.0 W/(m2 ·K)
Emissivity for heat radiation to environment
0.25
Initial die temperature
170 °C
Heat transfer coefficient to environment
50.0 W/(m2 ·K)
Heat transfer coefficient to workpiece
6000.0 W/(m2 ·K)
Emissivity for heat radiation to environment
0.25
Fig. 2. Set-up of preform (left) and finisher (right) forging process for simulation
Fig. 3. Changes in temperature fields in the forging obtained by numerical simulation
15 s and 120 s. Distributions of forging temperatures for forging cooling simulations are shown in Fig. 4.
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Fig. 4. Temperature fields in forging after cooling: 15 s (left), 120 s (right)
Fig. 5. Temperature fields in the preform (left) and finisher (right) lower mold cavities
In addition to measuring forging temperatures and estimating temperature fields in software, tool temperatures (in cavities) after forging operations were also measured. Figure 5 shows the cavity temperatures of the lower mould after the preform and finisher forging operations. The maximum temperatures are in the cavity zones, 174 °C in the cavity for preform forging, and 175 °C in the cavity for finisher forging operation.
3 Infrared Thermography and Temperature Measurement One of the most modern methods for measuring temperature is infrared (IR) thermography, which belongs to non-contact methods and is based on the principle of electromagnetic radiation emitted by each body. The emission coefficient ε is the quotient of the energy emitted by a real body at a certain temperature and the energy emitted by a black body at the same temperature. IR measuring devices receive infrared radiation and transform it into an electronic signal, after which a visual display of the temperature field is obtained. The intensity of infrared radiation is a function of the external body temperature. The measurement of temperature by IR thermography is not only based on the measured radiation, but also depends on the calibration of the device. It is necessary to accurately define and enter the value of the emissivity of the object material in order to obtain accurate results of temperature measurement [8, 12]. A FlukeTi400 IR camera was used in investigations presented in this paper. Before starting the temperature measurement in the industrial forging process, the emission coefficient ε = 0.80 was set in the device software, as this value gives a precise
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temperature measurement by the camera, identical to the measurement of the tool surface temperature by the contact temperature sensor. Due to the simultaneous measurement of temperatures in both the workpiece and the tool, a video mode of IR camera was used in order to have data on time intervals in the entire forging process, starting from heating the billet in induction furnace until cooling of finish fork forging and its disposal. Figure 6 shows the measured temperatures of hammer and mounted tools, as well as the billet in the induction furnace (Tmax = 1167.3 °C), and 3 s after removal, i.e. its transport to the forging hammer (Tmax = 1159.7 °C). Measured workpiece temperatures after preform forging operation, i.e. at the time of its placement in the preform cavity (Tmax = 1210 °C) shown in Fig. 7. After all forging operations, the finish forging was placed on a flat plate at room temperature and measured with an IR camera to cool it for 15 s (Tmax = 1187.9 °C) and 120 s (Tmax = 994.5 °C), respectively, as shown in Fig. 7. Figure 8 shows the temperatures of the cavities in upper mould before the start of the forging process and after all forging operations. Due to the position of the mould and the shooting angles of the IR camera, the IR images were recorded a few seconds after removing the forging and opening the moulds, so that the tool temperature dropped for those few seconds. It can be assumed that the tool temperatures were higher at the end of the forging process from those shown in the figure.
Fig. 6. Temperatures of hammers/tools, billet in the furnace, and after 3 s of cooling
Fig. 7. Temperature of fork forging in preform cavity and after cooling for 15 s and 120 s
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Fig 8. Temperatures of the upper mould before and at the end of the forging process
4 Result Analysis and Discussion The temperature of the heated billet in the induction furnace measured by the IR camera is identical in the first numerical simulation of the heating process of the billet, considering the set values from the industrial process. After the transfer of the billet to the forging hammer, in the period of 3 s, its surfaces cooled down, so the measured temperatures, shown in Fig. 6 are in the range of 1150–1157 °C, which is close to the temperatures obtained in the simulation, in come temperature points in Fig. 3 (e.g. 1148 °C). If we look at the temperature field in the workpiece after the second hammer blow, it is noticeable that in the numerical simulation a maximum temperature of 1210 °C obtained, which corresponds to the image of the workpiece in the same forging phase, which is placed in the preform cavity (Tmax = 1210 °C), as shown in Fig. 7. The same figure shows the IR image of the fork forging after all forging operations which is partially cooled due to transport for 15 s with the maximum forging temperature of 1187.9 °C. Figure 4 shows the temperature fields obtained by numerical simulation of forging cooling in the same period of 15 s and the maximum temperature of the virtual forging is 1180°C (Fig. 7). In the further cooling period for 120 s, there is a further drop in temperature, by about 190 °C as measured by an IR camera (Tmax = 994.5 °C). In the numerical simulation of further forging cooling, the results show a decrease in temperature by about 185 °C in the same period of time, since Tmax = 994.8 °C (Fig. 4). Comparing these results of numerical estimation of thermal effects with IR measurements, a satisfactory agreement is evident. This is not the case when comparing tool temperatures measured by an IR camera and estimated by a numerical simulation. As can be seen in Fig. 8 the heating of the tool before forging is only local in the engraving cavity zones so that the maximum measured temperature is 167.4 °C in the preform cavity zone and 120.9 °C in the finisher cavity zone, while the temperature of the rest of the mold is around 80 °C. In contrast, in the numerical simulation, a homogeneous temperature is given in the whole tool of 170 °C. Between each operation, the tools are lubricated and cooled with graphite emulsion, which was not taken into account in the process simulation. Recording the tool with the IR camera was possible only after opening the moulds and removing the workpiece, which takes a few seconds, so that during this period there is additional cooling of the tool.
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However, given the good agreement between the estimated and measured temperature fields in the forging, the results of numerical simulation and estimation of temperature fields in the tool can show zones with critical temperatures in which thermal cracks and accelerated tool wear can occur.
5 Conclusion The application of IR thermography for the identification of temperature fields in the workpiece and the tool during the forging process is the safest way of contactless measurement, because the application of other methods is difficult due to high temperatures and danger to the operator. Proper definition of the material emission coefficient and adjustment of the measurement range, enables the detection of zones with a precisely defined temperature range.However, an IR camera can only detect and measure temperatures on visible surfaces, and the measured values can sometimes depend on the “viewing angle” and the changed emissivity of the material as a result. Therefore, the complementary application of experimental measurements by IR thermography and numerical simulations is a way to obtain complete temperature fields in the workpiece and tool, at any stage in the process, in the entire forging and tool volume, at any point or cross section. In order for the temperature field estimation to be as accurate as possible, the simulation parameters and the corresponding material coefficients based on IR measurements should be set. It is desirable to simulate local heating of forging cavities, as is the case in industry, and on that basis to do further numerical experiments. In addition to the simulation of a real industrial process, one can further investigate on virtual models by changing the process parameters and obtain the desired process conditions and forging quality, from the aspect of controlled temperature regimes. Acknowledgements. The paper includes research conducted within the project TR34002, funded by the Ministry of Education, Science and Technological Development of Serbia.
References 1. Mandic, V.: Model-based manufacturing system supported by virtual technologies in an industry 4.0 context. In: Wang, L.., Majstorovic, V.. D.., Mourtzis, D.., Carpanzano, E.., Moroni, G.., Galantucci, L.. M.. (eds.) Proceedings of 5th International Conference on the Industry 4.0 Model for Advanced Manufacturing, pp. 215–226. Springer, Cham (2020) 2. Mandic, V.: Virtuelni inženjering, Mašinski fakultet, Kragujevac (2007) 3. Mandic, V., Stefanovic, M., Gavrilovic, Z.: Development of the forging technology for producing the artificial hip stem through application of virtual manufacturing. In: Proceedings of XII International Conference KODIP, pp. 96–105 (2014) 4. Xia, H., Guo, X.-L., Ji, C.-C.: Numerical simulation of blank-making roll forging process for heavy automotive front axle. In: Proceedings of the 1st International Conference on Mechanical Engineering and Materials Science (2012) 5. Movrin, D., Milutinovic, M., Plancak, M., Skakun, P.: Optimization and design multistage hot forging processes by numerical simulation and experimental verification. . J. Technol. Plast. 35, 1–2 (2010)
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6. Cancelos, R.L., Varas, F., Martin, E., Viéitez, I.: Analysis of the thermo-mechanical deformations in a hot forging tool by numerical simulation. IOP Conf. Ser. Mater. Sci. Eng. 119, 12–21 (2016) 7. Zhang, Y., Wei, B., Fu, X.: An usteady temperature field measurement method for large hot cylindrical shell forging based on infrared spectrum. Measurement 58, 12–21 (2014) 8. Usamentiaga, R., Venegas, P., Guerediaga, J., Vega, L., Molleda, J., Bulnes, F.G.: Infrared termography for temperature measurement and non-destructive testing. Sensors 2014(14), 12305–12348 (2014) 9. Thajeel, H.A.: Numerical modeling of infrared thermography technique via ANSYS, Master Theses, 7344 (2013) 10. Simulating reality. MSC Softw. Mag. 5 (2015) 11. Mocellin, K., Terzolo, L.: Modelling of tools heating in hot forging processes. In: 8th International Conference on Advanced Computational Methods in Heat Transfer, pp. 120–128 (2004) 12. Du, S.: Infrared imaging, Infrared imaging – case studies and applications, Theses, 268, New Jersey Institute of Technology, New Jersey (2016)
Supplement to the Standard VDI/DGQ 3442 with Gage R&R Study Branko Štrbac(B) , Miloš Ranisavljev, Milan Zeljkovi´c, Miloš Knežev, and Miodrag Hadžistevi´c Faculty of Technical Sciences, Department of Production Engineering, University of Novi Sad, Novi Sad, Serbia [email protected]
Abstract. Due to strict functional product requirements designers are compelled to create products with very tight tolerances. Therefore, strict requirements are set for production and measurement processes with regard to accuracy. This research is based on the application of the VDI/DGQ 3442 standard for the assessment of accuracy of numerical control machine tools.The standard is supported by the study of repeatability and reproducibility of the measuring instrument with the aim of dividing total variability of results into the measuring instrument variability and production variability. This is a way to avoid the complex procedure for assessing measurement uncertainty of the CMM used in the verification procedure. Keywords: Accuracy machine tools · Measurement system analysis · GR&R · CMM
1 Introduction The functional requirements of contemporary mechanical products are becoming increasingly complex. Consequently, manufacturing processes have to satisfy strict criteria concerning the permissible deviation of real geometry from the nominal (ideal) geometry. Therefore, a high level of accuracy is required from the production processes but also the verification (measurement) process. The measurement quality report must be present in the measurement result and the imperfection of the measuring instrument narrows the tolerance field left for processing.Accuracy analysis of machine tools is an essential task during the entire life cycle of the machine: from the design and production phase, through the installation and operation phase, all the way to the end of the life cycle. The accuracy of the machine tool directly affects the accuracy of the dimensions, shape, and roughness of the surfaces of the machined workpiece. Hence, one of the key reasons for analyzing the accuracy of the machine tool is the verification and assessment of the machine’s ability to make products according to construction tolerances and specifications. The general goal of accuracy testing is to measure and document all possible machine tool faults to determine their sources, understand the behavior of the characteristics of physical components, and quantify their impact on overall performance.Two
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 350–356, 2021. https://doi.org/10.1007/978-3-030-75275-0_39
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known standards for performance testing are NAS 979 and ISO10791-7. The NAS 979 test workpiece was proposed by the Aerospace Industries Association (AIA) for multiaxis milling machines [1, 2]. Standard VDI/DGQ 3442 proposes a statistical method for estimating the accuracy of numerically controlled lathes. The standard states that the working accuracy of the machine is evaluated based on making and measuring the diameter of the cylinder on the 25 samples [3]. Processing of test specimens is the most representative method for assessing machine performance conditions, including effects due to processing forces, although tests are performed under finishing conditions. The standard also recognizes the imperfection of the measuring instrument and suggests that the calculation should include the uncertainty of the measuring instrument with which the measurement was performed. Measurement uncertainty assessment is not a problem in the case of using conventional measuring instruments such as micrometer, calipers, or 1D-length measuring device.However, if a coordinate measuring machine (CMM) is used, estimating the measurement uncertainty is a very complex task and its value is inherent in the measuring task [4–6]. If the maximum allowable error (MPEE or MPEP ) is taken as the measurement uncertainty of the CMM, there is a high probability that an error will be made because these values refer to the uncertainty of the distance between two points and the uncertainty of the point. Since according to the standard it is necessary to determine the diameter of the cylinder processed on the machine tool, CMM measurement includes a sampling of several points from real geometry (number and position of points, geometric errors CMM, diameter of the tip of the probe are uncertainties) and estimation of substitutive geometry based on sampled points fitting algorithms (algorithm selection, the interaction of several points and positions with the fitting algorithm, filtering are also sources of uncertainty) [7]. To overcome this problem, the authors propose to include in the accuracy study of the machine tool according to the VDI/DGQ 3442 standard, instead of measurement uncertainty, the variability of the measuring instrument through conducting a reproducibility and reproducibility (GR&R) study.This study has the possibility of dividing the total variability in the measurement results into variability resulting from the difference between the manufactured parts (variability of the machining process) and variability resulting from the measuring instrument expressed in percent. Gage repeatability and reproducibility studies are widely used as an indicator of CMM measurement variability. Also, this paper aims to compare the standard procedure with GR&R where the value of measurement uncertainty will be adopted based on previous research. If closeness is obtained between the two applied methodologies, the general conclusion will be that the working accuracy of the machine tool can be determined based on the analysis of the measuring system following the guidelines of VDI/DGQ 3442 regarding process parameters, tools, and analyzed quality characteristics.
2 Methodology To assess the accuracy of the CNC lathe INDEX GU 600, a workpiece of carbon steel shown in Fig. 1 was machined. Measurement of dimension d = φ50 mm was performed on a Carl Zeiss Contura g2 RDS, coordinate measuring machine whose maximum permissible error amounts to MPEE = 1.9 + L / 330) μm (L is the length of measurement
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expressed in mm). The passive VAST XXT sensor was used for sampling in the “pointby-point” mode with Rpt , MPE = 1 μm repeatability, Fig. 2. 25 manufactured parts were measured after temperature stabilization in an air-conditioned laboratory with the same measurement strategy, the working subject is located at the same place in the measured volume, the least-squares method was used to obtain the substitutional geometry. According to the VDI/DGQ 3442 standard, the working accuracy is calculated according to the form (1): AS = 6sR3 ,
(1)
where As is the operating accuracy and sR3 is the standard deviation calculated from form (2): 2 − s2 (2) sR3 = sR2 R1 sR2 represents standard deviation calculated from the measured parts and sR1 the standard deviation as a component of the measurement system uncertainty.
Fig. 1. Test workpiece for testing working accuracy by statistical method according to VDI 3441.
Fig. 2. Workpiece measurement on CMM
Conducting the GR&R study, 10 workpieces were randomly selected, taking care that the variability of processing was included in this sample. Each workpiece was measured three times (repeatability) by three operators (reproducibility) at random (crossed study) [8–11]. Each time the operators varied the position of the workpiece in the volume of the CMM and the measurement strategies were different due to the inclusion of as many factors of the uncertainty of the CMM as possible [12]. Variance analysis (ANOVA) was used to conduct the study, which provides the possibility of detecting the interaction between workpieces and operators. A schematic representation of GR&R is shown in Fig. 3.
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Fig. 3. Graphical representation of the GR&R study
3 Results and Discussion Deviations from the nominal measure expressed in μm for 25 workpieces are shown in Table 1. According to the recommendations of the standard, the working accuracy of the machine As = 8.656 μm was obtained. The value of the measurement uncertainty of the CMM was adopted based on the research presented in [4]. Table 1. Values of deviations from the nominal value 1 2
3
4
5
1 6 11 11
8 9
2 7
6 8
9 11
3 8 12
8 10 9
4 6
9
9
5 8
7 10 10 8
9 9
The Minitab 17 software was used to conduct the GR&R study. The results of the analysis are shown in Tables 2 and 3 and Fig. 4. The conclusion from Table 2 is that the differences in the workpieces are statistically significant (p < 0.05) where are the differences between the operators, as well as the interactions between the operators and the parts, have no statistical significance (p > 0.05).
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Gage R&R study – ANOVA method Two-way ANOVA table with interaction Source
SS
MS
F
P
Part
DF 9
0.0021853
0.0002428
84.5529
0.000
Operator
2
0.0000050
0.0000025
0.8730
0.435
Part * Operator
18
0.0000517
0.0000029
0.8447
0.643
Repeatability
60
0.0002040
0.0000034
Total
89
0.0024460
α to remove interaction term = 0.05
Table 3. GR&R study Source
VarComp
%Contribution (of VarComp)
StdDev (SD)
Study Var (6 × SD)
%Study Var (%SV)
0.0018105
0.0108629
33.11
Total Gage R&R 0.0000033
10.97
Repeatability
0.0000033
10.97
0.0018105
0.0108629
33.11
Reproducibility
0.0000000
0.00
0.0000000
0.0000000
0.00
Operator
0.0000000
0.00
0.0000000
0.0000000
0.00
Part-to-part
0.0000266
89.03
0.0051589
0.0309536
94.36
Total variation
0.0000299
100.00
0.0054674
0.0328044
100.00
Number of distinct categories = 4
Table 3 shows the results of the GR&R study. It can be seen that the share of the variability of differences between parts is 89.03%. However, based on the recommendations, the measurement system is not acceptable for this study because the %Study Var is > 30%. Also, the value of Study Var (6 × SD) for Part-to-part is 30.9 μm which is much higher than the value obtained by applying the standard VDI/DGQ 3442. It can be concluded that the assumption is not suitable and that using GR&R study it is not possible to assess the accuracy of the machining center, at least not in the domain as obtained by applying the standard method. However, it should be borne in mind that operators during GR&R are measured by including as many uncertainties as possible in the measurement process. The result is much larger differences in results compared to measuring 25 workpieces with the same strategy. This study represents a pilot study on this topic and further research will help to analyze in more detail the possibility of comparing the two methodologies.
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Gage R&R (ANOVA) Report for Diameter Gage name: Date of study:
Reported by: Tolerance: Misc:
CMM Carl Zeiss Contura g2 RDS 18.01.2021.
Assistant Professor
Components of Variation
Percent
100
Diameter by Part % Contribution % Study Var
48.28
48.27
50
48.26 0
Gage R&R
Repeat
Reprod
1
Part-to-Part
4
8
Sample Range
Dejan
Ilija
Miloš
0.004 0.000
13
48.28
_ R=0.00306
20
48.27
24
48.26 Dejan
Ilija
Dejan
Ilija
Miloš
Operator
Xbar Chart by Operator
Part * Operator Interaction
Miloš
__ UCL=48.27002 X=48.26689 LCL=48.26376
48.27
Average
48.28
48.26
21
LCL=0
Part
Sample Mean
18
Diameter by Operator UCL=0.007877
1 4 8 11 13 15 18 2 0 2 1 2 4 1 4 8 11 13 15 18 20 21 24 1 4 8 11 13 15 18 2 0 2 1 2 4
48.28
15
Part
R Chart by Operator 0.008
11
Operator Dejan Ilija Miloš
48.27
1 4 8 11 13 15 18 2 0 2 1 2 4 1 4 8 11 13 15 18 20 21 24 1 4 8 11 13 15 18 2 0 2 1 2 4
Part
48.26
1
4
8
11
13
15
18
20
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Part
Fig. 4. Graphic representation of the GR&R study
4 Conclusion It is a great imperative for machining processes and measurement systems in terms of accuracy and it is necessary to have information about their quality. There are several methodologies for assessing the accuracy of machining systems. This study dealt with the assessment of the accuracy of a CNC lathe and used the methodology proposed in VDI/DGQ 3442. The results of this study were compared with the results of GR&R analysis to examine the feasibility of measuring system to assess the accuracy of the machining system. This theory is based on the fact that GR&R breaks down the total variability in the measurement results into components, including the component resulting from the processing. The case study showed large deviations of the proposed method from the standard.
References 1. NAS 979: uniform cutting test, NAS series, metal cutting equipment specifications, pp. 34–37 (1969) 2. ISO 10791 series, Test conditions for machining centres, International Organi-zation for Standardization (1998) 3. VDI-DGQ 3442:1978, Statische Prüfung des Arbeits- undPositionsgenauigkeit von Drehmaschinen, VDI-Verlag
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4. Štrbac, B., Aˇcko, B., Havrlišan, S., Matin, I., Savkovi´c, B., Hadžistevi´c, M.: Investigation of the effect of temperature and other significant factors on systematic error and measurement uncertainty in CMM measurements by applying design of experiments. Measurement 158, 107692 (2020) 5. Wilhelma, R.G., Hockena, R., Schwenkeb, H.: Task specific uncertainty in coordinate measurement. CIRP Ann. Manuf. Technol. 50, 553–563 (2001) 6. Štrbac, B., Radlovaˇcki, V., Spasi´c-Joki´c, V., Deli´c, M., Hadžistevi´c, M.: The difference between GUM and ISO/TC 15530-3 method to evaluate the measurement uncertainty of flatness by a CMM. MAPAN 32, 251–257 (2017) 7. Kruth, J.P., Van Gestel, N., Bleys, P., Welkenhuyzen, F.: Uncertainty determination for CMMs by Monte Carlo simulation integrating feature form deviations. CIRP Ann. Manuf. Technol. 58(1), 463–466 (2009) 8. AIAG, Measurement Systems Analysis Reference Manual, 4th edn. (2010). https://www.ama zon.com/Measurement-SystemsAnalysis-MSAAIAG/dp/B004Z0V40G 9. Ha, C., Kim, D., Park, S.: Assessment of the adequacy of gauge repeatability and reproducibility study using a Monte Carlo simulation. Math. Probl. Eng. 2017, 1–15 (2017) 10. Marques, R.A.M., Pereira, R.B.D., Peruchi, R.S., Brandão, L.C., Ferreira, J.R., Davim, J.P.: Multivariate GR&R through factor analysis. Measurement 151, 107107 (2020). https://doi. org/10.1016/j.measurement.2019.107107 11. Ranisavljev, M.: Gage Repeatability and Reproducibility study of Coordinate measuring machine, Bechelor thesis (2020) 12. Hocken, R., Pereira, P. (eds.): Coordinate Measuring Machines and Systems, 2nd edn. CRC Press (2011)
Surface Characterization of the Cobalt-Based Alloy Stents Fabricated by 3D Laser Metal Fusion Technology Dmytro Lesyk(B) , Oleksandr Lymar, and Vitaliy Dzhemelinkyi Laser Systems and Physical Technologies Department, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine [email protected]
Abstract. The paper focuses on surface characterization of cardiovascular metal stents fabricated by a promising laser-based additive manufacturing technique. The prototype stents were developed and printed by the laser powder bed fusion (LPBF) process using a biocompatible Co-Cr alloy powder. The chemical composition and microanalysis of the powder and LPBF-built alloy are addressed. The stent geometry, strut thickness, surface morphology, and defects on the surface of the 3D-printed stent strut are also studied. Results indicated that the LPBF-built stent test parts are characterized by the required geometrical accuracy, having the chemical composition without changes. The rough surface is formed in the 3D printed stents, containing various the surface defects. The macrodefects in the LPBF-built Co-Cr alloy stents were not found. Keywords: 3D printing · Laser powder bed fusion process · Co-Cr powder · Cardiovascular stent · Chemical composition · Stent geometry · Surface morphology
1 Introduction The main challenges associated with medical stents are geometry, material, manufacturing process, and post-processing [1]. The metals or polymers are used for the manufacture of modern stents. Compared to the polymer stents, the metal stents are characterized by a high structural rigidity with corrosion resistance and thermal stability during implantation as well as the ability to self-expansion. The stainless steel and alloys of titanium, chromium and cobalt are most often used for the metal stents production. Nowadays a novel additive manufacturing or three-dimensional (3D) printing technology is applied for the producing of polymer and metal components [2–5]. This technology allows eliminating multiple manufacturing constraints producing complexly shaped metal components with high precision under computer control as compared to the conventional manufacturing techniques [6]. As a result, the 3D printing technology presents huge potential to manufacture both non-metal and metal biomedical components. Whether for individual implants or for micro-implants with medicine depots, 3D printing is ideally suited for manufacturing such parts [4, 7–10]. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 357–364, 2021. https://doi.org/10.1007/978-3-030-75275-0_40
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Currently, the stereolithography (SLA), fused filament fabrication (FFF), and electrospinning (SE) techniques can be used to manufacture the polymeric biomedical products while the metal components can be printed by 3D powder bed fusion techniques, such as a binder jetting (BJ), multi jet fusion MJF, selective laser sintering (SLS) or direct metal laser sintering (DMLS), and electron beam melting (EBM) or selective laser melting (SLM) [3, 7, 11–13]. As the metal has casting limitations, the highly automated selective laser melting or laser powder bed fusion (LPBF) process could be a promising technique of additive manufacturing of the complexly shaped and small-sized metal components. The EBM and LPBF additive manufacturing methods are new technologies that have recently emerged. Compared to the SLS/LPBF techniques, the EBM technique provides a higher density of material, producing layers faster. At the same time, the surface texture is better after the LPBF process [14]. The EBM method can be used if the thin walls/struts of the parts do not require a thickness of less than 0.6 mm. Therefore, the additive manufacturing of metal stents with a strut thickness of less than 300 µm can be implemented by the LPBF technology, using highly concentrated laser beams with a diameter of 30…55 µm. For instance, a LPBF process allows coating electrodes for pacemakers with platinum, and producing nickel-titanium lattice structures [15] and stainless steel or cardiovascular cobalt-chromium stents [16–18]. The LPBFprinted metal stents are similar to those of conventional stents. Thus, the 3D laser metal fusion technology results in a reduction of the production cycle time due to the application of a single-stage manufacturing method instead of the microtube manufacturing and laser cutting phases, printing multiple stents simultaneously [17]. The aim of this work is to study the chemical composition, surface texture, and defects of the cardiovascular Co-Cr alloy stents manufactured by the LPBF process.
2 Experimental Procedures The stent test parts (~4 mm in external diameter, ~18.0 mm in length) with a 300 µm strut thickness were fabricated using a cobalt-based alloy powder. The nominal chemical composition of the cobalt-chromium (Co-Cr) powder given in wt% is the following: Co 59.0, Cr 25.0, W 9.5, Mo 3.5, Si 1.0, Mn < 1.0, Fe < 1.0, C < 1.0, and N < 1.0. The morphology of the used Co-Cr powder is illustrated in Fig. 1. The stent parts were produced with the 3D laser metal fusion process using an industrial MYSINT100 Dual Laser machine (building volume is 100 mm × 100 mm diameter), which was equipped with a maximum power 400 W ytterbium fiber laser (on the substrate) and a scanning optics (quartz F-Theta lens). In this work, the LPBF-built stent parts were printed in continuous laser mode using a laser power of 130 W and a laser scanning speed of 600 mm/s using a laser beam 55 µm in diameter. The measurement of the mass fraction of chemical elements in used Co-Cr powder was conducted by an EXPERT 3L–XRF high precision analyzer. The struts geometry and surface morphology of the PLBF-built stents was examined by an SEM-106I scanning electron microscope (SEM).
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Fig. 1. Morphology of the Co-Cr powder
3 Results 3.1 Chemical Composition The chemical composition of Co-Cr powder and LPBF-built stents is listed in Table 1. The main alloying Co, Cr, and W components of the used powder were checked by both high precision analyzer and energy dispersive spectroscopy (EDS). The chemical analysis of powder particles showed that the composition of the used powder meets its standards and is suitable for biomedical applications (bulk or porous surgical and dental implants, except medical stents). Table 1. Chemical composition of the Co-Cr powder and alloy in wt% Co
Cr
W
Mo
Si
Mn
Fe
C
N
Powder (ASTM)
59
25
9,5
3,5
1,0
≤1,0
≤1,0
≤1,0
≤1,0
Powder (analyzer)
58,43
24,83
9,58
4,0
0,78
0,67
0,084
-
-
Powder (SEM)_+1
57,88
25,41
9,74
4,37
0,95
0,91
-
-
-
Powder (SEM)_+2
55,78
25,10
9,75
4,64
1,3
0,73
-
-
-
Powder (SEM)_gen
58,30
26,46
9,05
4,00
0,80
1,39
-
-
-
Bulk (SEM)_+3
55,86
24,65
9,45
4,21
1,57
0,85
-
-
-
Bulk (SEM)_+4
57,26
25,17
9,81
4,53
0,88
0,98
-
-
-
The results of powder analysis by the SEM microscopy show that Co-Cr powder is characterized by a predominantly spherical shape (Fig. 2a). The nominal powder particle size was 15–65 µm. At the same time, it should also be noted that the irregularly
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shaped powder particles and satellite powder particles were observed. The existence of irregular or elongated powder particles may be due to a decrease in the distance between the plasma arc and the electrode due to the beating of the electrode during rotation during spraying. The study of the chemical composition (Table 1) of powder particles of irregular shape (Powder (SEM)_+1) showed its compliance with the composition of the alloy
+3
+2 +4
+1
(a)
(b) +2
+1
Fig. 2. SEM image and chemical composition of Co-Cr powder (a) and alloy (b)
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(Bulk (SEM)_+3) and powder particles of regular shape (Powder (SEM)_+2, Bulk (SEM)_+4). At the same time, it is also important to point out that the burning of the main chemical elements in the LPBF process did not occur (Table 1). Moreover, the chemical composition of the manufactured cardiovascular Co-Cr stents by the LPBF technology meets the requirements of ASTM for the studied alloy (Fig. 2b and Table 1). According to the results of chemical and microanalysis, it can be seen that the determined chemical composition of the powder granules is acceptable and corresponds well to the composition of the LPBF-built Co-Cr alloy stent, as well as correlates well with the relevant literature data (Table 1, Fig. 2) [3]. Langi et al. [19] also shown that the chemical composition for the LPBF-built tube and the commercial stent was similar. 3.2 Strut Geometry and Surface Morphology The LPBF-printed stent in the as-built condition is given in Fig. 3. The design of cardiovascular stents were developed taking into account the geometry of known commercial stents and successfully manufactured tubular stents using the additive laser metal fusion technology [17]. The SEM images of LPBF-built prototype stents were studied in the center of the stent (Fig. 3). It is of importance that the macrodefects in the LPBF-built stents were not observed. The thickness of the struts (300 µm) correlates well with the designed dimensions of the stent 3D model.
300 µm
Fig. 3. SEM observations of the LPBF-built Co-Cr alloy stents
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It is well-known that the reproducibility of the geometric dimensions of the structural elements of the manufactured SLM-stents is better when using compensation for the displacement of the laser beam. In this work, the amount of compensation for the displacement of the laser beam was 70 µm. These results are in good agreement with the published results [16, 17], where it was also found that the thickness of the struts is larger than the nominal due to the lack of laser beam compensation. As seen in Fig. 4, on the surfaces of the structural elements of the stents were found partially melted powder particles (blue arrow) or unmelted powder granules (yellow arrows), balling (green arrows) and the signs of the laser tracks (laser track boundary is marked with a red dashed line). As a consequence, the surfaces have a high roughness [17, 20, 21], which must be reduced by post-processing methods.
laser track boundary
Fig. 4. Morphology of the strut surface of the LPBF-built Co-Cr alloy stents
Thus, the LPBF-built stents suffer from the presence of manufacturing surface defects (Figs. 3 and 4). Therefore, thermal [22], chemical [17, 18, 23] or mechanical [24–27] post-processing of the 3D printed metal parts is required to reduce or eliminate the surface and structural defects. Recently, the chemical and electrochemical polishing was applied to reduce the surface roughness in the LPBF-built stents [17]. In particular, the surface roughness (Ra parameter) of LPBF-built Co-Cr-Mo alloy stents was decreased to ~1.5 µm from ~9.0 µm after electropolishing [16].
4 Conclusion In summary, this work shows the feasibility of additive manufacturing of the designed cardiovascular stents by the LPBF process. The macrodefects in the 3D printed stents were not found. Various surface defects (partially melted or unmelted powder particles, balling, and the signs of the laser tracks) were revealed on the surface of the stent strut.
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To decrease the surface roughness and eliminate surface defects in the LPBF-built CoCr alloy stents, the application of post-processing methods is planned in the further research.
References 1. Al-Mangour, B., et al.: The challenges: stent materials from the perspective of the manufacturer. Gastrointest. Interv. 2016, 98–104 (2013) 2. Aimar, A., et al.: The role of 3D printing in medical applications: a state of the art. J. Healthc. Eng. 2019, 5340616 (2019) 3. Yuan, L., et al.: Additive manufacturing of cobalt-based dental alloys: analysis of microstructure and physicomechanical properties. Adv. Mater. Sci. Eng. 2018, 8213023 (2018) 4. Ni, J., et al.: Three-dimensional printing of metals for biomedical applications. Mater. Today Bio. 3, 100024 (2019) 5. Culmone, C., et al.: Additive manufacturing of medical instruments: a state-of-the-art review. Addit. Manuf. 27, 461–473 (2019) 6. Bär, F., et al.: Laser additive manufacturing of biodegradable magnesium alloy WE43: a detailed microstructure analysis. Acta Biomater. 98, 36–49 (2019) 7. Ahangar, P., et al.: Current biomedical applications of 3D printing and additive manufacturing. Appl. Sci. 9, 1713 (2019) 8. Jamroz, W.: 3D printing in pharmaceutical and medical applications – recent achievements and challenges. Pharm. Res. 35, 176 (2018) 9. Caravaggi, P., et al.: CoCr porous scaffolds manufactured via selective laser melting in orthopedics: topographical, mechanical, and biological characterization. Soc. Biomater. 107, 2343–2353 (2019) 10. Hufenbach, J., et al.: Effect of selective laser melting on microstructure, mechanical, and corrosion properties of biodegradable FeMnCS for implant applications. Adv. Eng. Mater. 222, 2000182 (2020) 11. Guerra, A., Cano, P., Rabionet, M., Puig, T., Ciurana, J.: 3D-printed PCL/PLA composite stents: towards a new solution to cardiovascular problems. Materials 11(9), 1679 (2018) 12. Omar, M.A., et al.: Stent manufacturing using cobalt chromium molybdenum (CoCrMo) by selective laser melting technology. AIP Conf. Proc. 1901, 100017 (2017) 13. Langia, E., et al.: Characterisation of additively manufactured metallic stents. Proc. Struct. Integr. 15, 41–45 (2019) 14. Biemond, J.E., et al.: Bone ingrowth potential of electron beam and selective laser melting produced trabecular-like implant surfaces with and without a biomimetic coating. J. Mater. Sci. Mater. Med. 24(3), 745–753 (2013) 15. Yuan, L., et al.: Additive manufacturing technology for porous metal implant applications and triple minimal surface structures: a review. Bioact. Mater. 4, 56–70 (2019) 16. Finazzi, V., et al.: Design and functional testing of a novel balloon-expandable cardiovascular stent in CoCr alloy produced by selective laser melting. J. Manuf. Process. 55, 161–173 (2020) 17. Demir, A.G., et al.: Additive manufacturing of cardiovascular CoCr stents by selective laser melting. Mater. Des. 119, 338–350 (2017) 18. Finazzi, V., et al.: Design rules for producing cardiovascular stents by selective laser melting: geometrical constraints and opportunities. Proc. Struct. Integr. 15, 16–23 (2019) 19. Langi, E., et al.: Characterisation of additively manufactured metallic stents. Proc. Struct. Integr. 15, 41–45 (2019) 20. Lesyk, D.A., et al.: Post-processing of the Inconel 718 alloy parts fabricated by selective laser melting: effects of mechanical surface treatments on surface topography, porosity, hardness and residual stress. Surf. Coat. Technol. 381, 125136 (2020)
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Analysis of the Behavior of the Ash Depending on the Temperature of Combustion and Air Supply System Nihad Hodzic1(B) , Anes Kazagic2 , and Kenan Kadic2 1 Faculty of Mechanical Engineering Sarajevo, University of Sarajevo, Sarajevo,
Bosnia and Herzegovina [email protected] 2 JP Elektroprivreda BiH d.d. - Sarajevo Power Utility, 71000 Sarajevo, Bosnia and Herzegovina
Abstract. The choice of the appropriate combustion technology is primarily related to the overall physico-chemical properties of fuel, primarily the properties of solid fuel, which also contains a mineral matter. The higher the content of fly ash in the fuel, the more complex the choice of the appropriate combustion technology. In addition to knowledge about the chemical composition of ash and the ash melting temperatures, the choice of combustion technology also requires knowledge about the behavior of ash in this process at different temperatures and technical-technological conditions in the furnace. This paper presents the results of laboratory research on the behavior of fly ash during the combustion of Bosnian coals from Middle Bosnian mining basin, and co-firing coal with waste woody biomass. The research was conducted on reactor installed in the laboratory for coal and biomass combustion at the Faculty of Mechanical Engineering, University of Sarajevo. The test fules powdered were subjected to pulverized combustion with a variable combustion temperature, the excess air ratio and the system of air supply into the reaction zone. During the test regime, samples of ash deposits from the reaction zone from different places and samples of slag and ash at the reactor outlet were collected. In assessing the behavior of ash in the process and the tendency to slagging/fouling heating surfaces in the boiler, in addition to the classic criteria applied for these purposes, the criteria determined in the overall previous research in the laboratory for coal and biomass combustion were applied. These criteria also include the influence of process temperature on the ash behavior in the process. Keywords: Reactor · Coal · Combustion · Ash · Slag
1 Introduction It is known that Bosnia and Herzegovina has significant coal deposits and reserves and that the existing electricity system is mostly based on the use of coal as a primary fuel in electricity generation. Such a setting will certainly be maintained in the following period, although the production of coal-based electricity is increasingly financially and © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 365–373, 2021. https://doi.org/10.1007/978-3-030-75275-0_41
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normatively burdened, which makes it increasingly difficult to compete in the liberalized electricity market. Although the balance and exploitation reserves of coal in Bosnia and Herzegovina amount to about 4.5 bilion t, of which about 40% refers to brown coal and about 60% to lignite, [1], due to the aforementioned reasons in the regular operation of existing thermal power plants, and possibly future ones, it will be necessary to introduce other fuels such as e.g. waste woody biomass, short rotation copies, energy crops or RDF/SRF. So, at least for some boilers within the existing thermal power plants whose operation lifetime has been extended by revitalization, the introduction of co-firing in regular operation is not only imperative but also a significant increase in competitiveness and a safer perspective. The basic characteristics of BH coal are low heating value (LHV), high ash and moisture content and poor reactivity, where the quality of these coals varies significantly from one mining basin to another, and even from one mine to another within the same mining basin, [2]. Consequently, there are various technical and technological problems in the combustion of these coals, including instability and interruption of the combustion process and especially, due to significantly different and variable properties of fly ash and component coals in the mixture of these coals, frequent and intensive slagging/fouling of boilers surface that quite often escalates to the level of slagging and forced exclusion of the plant, [2, 3]. On the other hand Bosnia and Herzegovina also has significant energy potential from waste biomass derived from agricultural production and forestry, primary and secondary wood processing. It is estimated that the total annual technical energy potential of biomass remains in BiH is more than 33 PJ, which is equivalent to more than 3 million tons of BIH lignite, [4]. In principle, the use of biomass as a fuel has a significant and positive effect on reducing CO2 emissions from coal-fired power plants, [4]. There are many examples of existing coal-fired power plants that have included biomass in the combustion process, and from their experience it has been shown that the share of biomass in a mixture with coal is different, but does not exceed the value of 20%, [6]. There are several reasons for this, the most common of which are: the need to change or at least harmonize the fuel supply system from the depo to the furnace including thermal and mechanical fuel preparation, changing the thermal load of boiler components and the boiler as a whole; significant differences in the properties of the mineral matter of the fuel in coal and biomass. The influence of the mineral matter from biomass during co-firing with coal on the processes and intensity of slagging/fouling of heating surfaces has not been studied enough because these processes and phenomena cannot be generalized because their development depends exclusively on the properties of the mineral matter of the fuel the boiler as a whole. The study of the tendency of ash to slagging/fouling heating surfaces in the combustion of solid fuels is generally based on the assessment of the intensity of deposition and the characteristics of ash deposits formed under certain combustion conditions, [6, 7]. Also, in this case as well, the assessment
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of the propensity to slagging/fouling is made on the basis of the characteristics of the ash deposits collected - label, formed under certain ambient combustion conditions. In principle, the label is analyzed by visual and physical methods. Here, in order to assess the possible impact of primary measures in the furnace1 on the shape and condition of solid combustion products and related pollution of heating surfaces, 4 out of 6 criteria established for this purpose were used in previous research in the Laboratory for coal and biomass combustion at the Faculty of Mechanical Engineering, University of Sarajevo2 , [7, 8]: label shape, label condition, label structure and label adhesion. Based on these criteria, a description of the characteristics of deposits, slag and ash for different test fuels during combustion at a given temperature and in conditions with or without staged supply of combustion air was performed. The assessment of propensity to slagging/fouling for a given fuel and the given combustion conditions is given through descriptive terms as follows: low, moderate, strong and very strong slagging/fouling, [7–9].
2 Fuel Test Matrix, Test Regimes and Laboratory Plant Fuel Test Matrix and Test Regimes: For the purpose of these laboratory researches, a matrix of basic test fuels was formed, [9–11] - Table 1: – Blend of coal from the mines Kakanj, Breza and Zenica with mass fraction of component coal 70, 20 and 10%, respectively - fuel label: K70B20Z10. This coal mixture is formed after drying and grinding of component coals in a laboratory mill. – The blend of coal that was created by mixing component coals delivered to the TPP depot from several mines (Kakanj, Breza, Zenica, Graˇcanica, Livno, Nova Bila, Banovi´ci, …) and the percentage of approximately delivered quantities of coal from these mines and which in recent years usually incinerated in TPP Kakanj (fuel label: U100) in combination with waste woody biomass (beech and spruce sawdust, fuel label B100) with a biomass content of a mixsture of 7% and 10% - fuel labels: U93B7 and U90B10. Both of these mixtures of coal with wood biomass are excluded in the plant behind the mills (drive process mixture). These solid fuels are subjected to laboratory research of combustion in the conditions of classical and staged supply of combustion air to the furnace as well as in the conditions of different values of process temperature: 950 ÷ 1350 °C, and 1350 ÷ 1450 °C. These combustion temperature ranges correspond to the combustion conditions in PC boilers with slag tab furnace In all test regimes, ceramic tablets for collecting deposit samples were placed in the same place in the flue gas stream behind the OFA air inlet, Fig. 1.
1 ) Primary, this means staged supply of combustion air. 2 ) In essence, criteria based on the visual method were used.
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K70B20Z10 U93B7 U90B10
Moisture %
10.71
18.09
14.67
Ash %
40.84
33.05
34.14
LHV kJ/kg
13171
12510
12655
SiO2
46.30
40.42
40.17
Fe2 O3
9.86
9.18
10.06
Al2 O3
15.48
17.21
16.93
CaO
11.98
14.76
14.69
MgO
5.76
1.60
2.94
SO3
7.04
7.08
9.10
TiO2
0.40
0.40
0.41
Na2 O
0.38
5.533
2.95
K2 O
1.07
2.246
1.61
1210
1250
1240
Mineral analysis of ash, %
Ash temperatures, °C t2 - softening t3 - hemisphere
1250
1280
1270
t4 - flow
1270
1310
1300
ZONE 2
1,3 m OFA 2 RT
t2, 1,76 m
ZONE 1
CD t1, 2,39 m Sampling of ash deposits MP FGA PID regulation of underpressure
Sampling of ash and slag Water-cooled probe
Fig. 1. Principal scheme of the experimental furnace - bottom; RT - reaction tube, MP-FGA measuring point / flue gas analysis, CD - command desk
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3 Results of the Research a) Fuel K70B20Z10 Temperature 950 °C: Deposits from ceramic tablets during combustion with staged air supply (λ1 /λ = 0.95/1.15) and with classical combustion air supply to the reaction zone were compared (λ1 /λ = 1.15/1.15), Fig. 2. In both cases, the samples are conical/hemispherical in shape, gray color, with a distinctly loose granular structure which, under the influence of gravity (already at a slight inclination of the ceramic tablet), easily and completely wraps around the ceramic tablet.
Fig. 2. Deposit from ceramic tablet: K70B20Z10, 950 °C, sa OFA, λ1 /λ = 0.95/1.15 - left; without OFA, λ1 /λ = 1.15/1.15 - right
Practically, there is no difference between these two samples, so it is concluded that at a combustion temperature of 950 °C the primary degree of combustion air in the part of the boiler behind OFA has no effect on the shape and condition of deposits on uncooled surfaces. The fly ash under such combustion conditions in the zone of the furnace behind OFA is not prone to the formation of larger deposits or fouling/slagging of boiler heating surfaces. Temperature 1250 °C: In this case the deposit from the ceramic tablet is flattened, pale yellow in color, forms partly fused grains of smaller dimensions, the deposit is on the verge of disintegration, blown away easily from the tablet, Fig. 3. After carrying on the surface ceramic tablets remain smaller particles that are more tightly bound but still not hard-to-remove. Ceramic tablet in this experiment simulates a boiler heating surface that is not or is poorly cooled (for example secondary deposits on heating surfaces), it is concluded that in such conditions in the real process could additionally grow (already formed) deposits.
Fig. 3. Deposit from ceramic tablet: K70B20Z10, 1250 °C and λ1 /λ = 0.95/1.15
In real boiler operation, it is necessary to timely remove the formed primary deposits from the heating surfaces both due to their negative impact on heat transfer, and due to
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the possibility of forming secondary deposits of different properties (often unfavorable) in relation to these deposits to primary (surfaces that are not intensively cooled). On the other hand, the exempt deposit from the top of the water-cooled probe has different characteristics, as does the slag sample from the bottom of the reactor, Fig. 4. The sample at the top of the probe is gray-black color, distinctly loose granular structure while the slag from the bottom of the reactor forms for the most part a larger structure with pieces up to about 2 cm in size that are brittle and are broken by the application of a small force - a slight pressure with the finger.
Fig. 4. K70B20Z10, 1250 °C and λ1 /λ = 0.95/1.15: deposit with water cooled probe - left, slag from the bottom of the reactor - right.
Temperature 1350 °C: The deposit sample is flattened/cylindrical shape, predominantly yellow-black color, compact and firm and firmly attached to the ceramic tablet significant shear force is required at the joint to remove deposits from the ceramic tablet surface, Fig. 5. However, the deposit removed from the top of the probe is still crisp with a granular structure that separates very easily and completely from the probe, Fig. 5.
Fig. 5. K70B20Z10, 1350 °C and λ1 /λ = 0.95/1.15: deposit from ceramic tablet - left, larger fused granules in a compact cylindrical sample on tablet - in the middle, deposit with water cooled probe - right
The slag from the bottom of the reactor is predominantly larger, fused, with hard pieces that are irregularly shaped. Significant force is required to shred the slag. On the other hand, the ash, which excluded from the flue gas tube, is very fine granulation, gray color and very loose, Fig. 6. The mutual interactions of the components from the ash at different temperature conditions on their way through the boiler to the sampling/separation site result in the redistribution of these components. An example of such redistribution of components depending on the combustion temperature, observed at the macro level of the process (input - output), for this mixture of coal K70B20Z10 is in Fig. 7 - the results refer to samples of deposits from ceramic tablets and slag from the bottom of the furnace.
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Fig. 6. K70B20Z10, 1350 °C and λ1 /λ = 0.95/1.15: slag from the bottom of the reactor - left, ash from the flue tube - right.
K70B20Z10: Depozit
1350
K2O
Na2O
1150
Na2O
TiO2
950
K2O
1350 1250 1150
TiO2
Ugalj
SO3
K70B20Z10: Šljaka
Ugalj
SO3
MgO
MgO
CaO
CaO
Al2O3
Al2O3
Fe2O3
Fe2O3
SiO2
SiO2
0
10
20
30 Sadržaj, %
40
50
60
0
10
20
30 Sadržaj, %
40
50
60
Fig. 7. Comparative presentation of the composition of coal ash, deposits from the reaction zone and slag from the bottom of the reactor as a function of combustion temperature, label: Ugalj = Coal = U100, Šljaka = Slag
b) Fuel U93B7 i U90B10 Temperature 1350 ÷ 1450 °C: The condition and form of deposits from ceramic tablets in the co-firing of coal and woody biomass U93B7 and U90B10 is presented in Fig. 8, which shows the form and structure of the deposit.
Fig. 8. At λ1 /λ = 0.95/1.15: a) U93B7/1350 °C, b) U93B7/1400 °C, c) U90B10/1400 °C, d) U93B7/1450 °C - respectively.
From the previous results, it can be noticed that significant changes in the characteristics of ash deposits occur primarily due to changes in the combustion temperature. With the increase of the combustion temperature of the deposits, it becomes more and more coherent (the assessment of the deposit according to the cohesion criterion becomes strong, compared to moderate at lower temperatures), and the adhesion of the deposit to the ceramic tablet surface increases.
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4 Conclusion From the above presented results for the mixture of coal K70B20Z10, and based on the aggregation of the above criteria, it can be concluded that the combustion of this coal at a temperature of 950 °C is accompanied by weak slagging/fouling, ie. at this temperature in the boiler there should be no danger of the formation of deposits which may cause operating problems in the boiler. Furthermore, when burning this coal mixture in the process temperature range of 1150 ÷ 1250 °C, moderate slagging/fouling can be expected with ash deposits that are relatively easily removed from the surface of the sampler - these are the so-called. Easy-to-remove deposits. At temperatures of 1350 °C and above, solid fused deposits form, which bind more strongly to the substrate. It is obvious that in different temperature conditions different forms and characteristics of deposits or slag appear, depending on the place of sampling or the position of the heating surface in the boiler in real operation. The presented changes in the ash composition of boiler deposits, slag and ash in relation to the ash composition in coal are a side effect in real operation both in classical combustion and in combustion in the conditions of combustion air gradation. However, in summary, based on the results obtained in the study of combustion of coal mixture K70B20Z10 in terms of shape and condition of samples of deposits, slag and ash, it can be concluded that the degree of combustion air has no negative impact on slagging/fouling of boiler heating surfaces. The previous conclusions are very important because it has been shown, in relation to the previous opinion that the mixture of coal Kakanj, Breza and Zenica (as a base in the operation of current and future boilers in TPP Kakanj) can be burned unburned only in conditions with slag tap from combustion chamber, that it is technically-technologically possible and environmentally acceptable: combustion of pulverised fuel with dry removal of the slag from the furnace. The research of combustion properties of a mixture of coal and waste woody biomass was performed at process temperatures ≥ 1350 °C. The ash of the coal mixture is estimated to be very prone to soiling/slagging at the stated combustion temperatures. Acknowledgements. Part of the results presented in this paper were created during the research in the framework of the project: Labscale tests co-firing of coal, biomass and municipal waste aimed at the development of sustainable technologies within the circular economy, financed by the Ministry of Education, Science and Youth of Sarajevo Canton - Bosnia and Herzegovina for 2019/2020 and infrastructural assisted by the Faculty of Mechanical Engineering of Universtity of Sarajevo.
References 1. Studija energetskog sektora u BiH, Konaˇcni izvještaj, Modul 8 - Rudnici uglja, Konzorcij: Energetski institut Hrvoje Požar, Hrvatska; Soluziona, Španjolska; Ekonomski institut Banjaluka, BiH; Rudarski institut Tuzla, BiH (2009) 2. Uticaj kvaliteta uglja na troškove proizvodnje elektriˇcne energije i cijenu uglja; Studija; Naruˇcilac: JP Elektroprivreda BiH d.d. Sarajevo, Izvršilac: Mašinski fakultet Sarajevo (Lider) i Rudarski institut d.d. Tuzla (ˇclan), Sarajevo (2014)
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3. Smajevi´c, I., Hodži´c, N.: Betriebserfahrungen im Kraftwerk Kakanj bei der Verbrennung der starkverschmutzungsneigenden mitelbosnischen Braunkohle, Dresden, 25–26 Oktobar 2000, pp. 151–160 (2000) 4. Advanced Decentralised Energy Generation Systems in Western Balkans - ADEG, Projekt FP6, National Technical University of Athens, Institut IVD Stuttgart, Fakultet Strojarstva i Brodogradnje Zagreb, Mašinski fakultet Sarajevo, Institut Vinˇca, IST Portugal, Sarajevo (2004–2007) 5. Kazagi´c, A., Smajevi´c, I.: Experimental investigation of ash behavior and emissions during combustion of Bosnian coal and biomass. Energy 32(10), 2006–2016 (2007) 6. Kazagi´c, Smajevi´c, I.: Synergy effects of co-firing of wooden biomass with Bosnian coal. Energy 34(5), 699–707 (2009) 7. Kazagi´c, A.: Istraživanje specifiˇcnih problema sagorijevanja doma´cih ugljeva, magistarski rad, Mašinski fakultet Sarajevo (2006) 8. Kazagi´c, A., Smajevi´c, I., Dui´c, N.: Selection of sustainable technologies for combustion of Bosnian coals. Therm. Sci. 14(3), 715–727 (2010) 9. Hodži´c, N.: Istraživanje kosagorijevanja uglja i biomase usmjereno na smanjenje emisija primarnim mjerama u ložištu, Doktorska disertacija, Mašinski fakultet Univerziteta u Sarajevu, Sarajevo (2016) 10. Kazagic, A., Hodzic, N., Metovic, S.: Co-combustion of low-rank coal with woody biomass and miscanthus: an experimental study. Energies 11(3), 601 (2018) 11. Hodži´c, N., Kazagi´c, A., Smajevi´c, I.: Influence of multiple air staging and reburning on NOx emissions during co-firing of low rank brown coal with woody biomass and natural gas. Appl. Energy 168, 38–47 (2016)
Simulation Analysis of Underground Coal Mine Ventilation Systems Failure Edisa Nuki´c(B) and Edin Deli´c(B) Faculty of Mining, Geology and Civil Engineering, University of Tuzla, Tuzla, Bosnia and Herzegovina {edisa.nukic,edin.delic}@untz.ba
Abstract. This research focuses on the actual issue of possibility of predicting, visualizing and monitoring potential conditions of ventilation systems in failure with the aim of efficient situation management and ensuring conditions for saving human lives. Based on results of field measurements and laboratory analyzes, a model was developed for computer simulation of the contaminant distribution and changes in ventilation parameters with Hardy-Cross method using the VnetPC software package and the CFD software package “Fluent”. Simulation analysis of the ventilation systems failure mechanism identified ventilation branches that failed in cases of simulated hazards, determined the air flow, pressure losses, temperature, methane concentration and general distribution of contaminants and their intensity in individual branches of the ventilation system. The simulation analysis proposed in this paper enables testing of different scenarios for potential hazards as well as prediction of secondary ventilation system failures. Keywords: Underground coal mines · Ventilation system · Simulation analysis · VnetPC · Fluent
1 Introduction Underground coal mine ventilation system always operates with a certain risk and its failure cannot be ruled out even when extensive prevention measures are applied. For effective protection against unexpected events in coal mine, it is important to anticipate possible ventilation conditions and development of individual failures, in order to be able to effectively manage the situation. During severe failures, key information is usually missing or the reliability of information about processes and phenomena is limited [3]. Mining works take place in extremely heterogeneous environments, so it is difficult to predict all potential sources of danger and they can vary widely in a relatively small area. Underground coal mines are a very specific and complex due to long distances and depth, long ventilation paths, methane and other explosive and flammable gases and substances, sudden occurrence of toxic gases, harmful coal dust and a number of other adverse effects on workers. In real conditions in coal mines there are processes that cannot be analyzed by conventional methods. A serious challenge is to predict possible ventilation systems © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 374–384, 2021. https://doi.org/10.1007/978-3-030-75275-0_42
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failures, analyze their genesis, identify scale of influence, neutralization mechanisms, possible secondary failures or hazards, and to provide conditions for workers safety. The Law on Mining in Federation of Bosnia and Herzegovina [12] obliges mines to have a Defense and Rescue Plan, which must be created in regard to specific circumstances and specifics of the mine, updated in a timely manner and provide all preventive and operational measures and activities related to potential hazards. In order to develop a technical model for prediction and prevention of adverse effects of ventilation system or its individual components failure, a series of experimental measurements and laboratory analyzes were performed [6]; the results of it were used to identify potential sources of danger in analyzed cases: analysis of coal dust characteristics (flammability and explosiveness), analysis of coal propensity to spontaneous oxidation and gas composition. Measurements of fan effective pressure (depression), volumetric air flow, air flow rate, resistance, analysis of the air chemical composition, temperature measurements, and monitoring of oxidation processes occurrence were also performed. A series of experimental measurements were carried out on selected mine ventilation systems, with variations in individual parameters in order to be able to create and calibrate a numerical model for computer simulations. Since modern ventilation systems numerical analyzes are based on two methodologies application: modified Hardy-Cross (iterative process where assumptions of air flow as an incompressible fluid are introduced, ie constant density and equal volume flows of sum of inlet and outlet air currents) and calculation based on Navier-Stokes system of differential equations for the application of methods known as CFD (Computational Fluid Dynamics), therefore numerical analyzes with these methods also determine certain specifics in the application of different procedures. The Hardy-Cross method is suitable for “macroscopic” analyzes of ventilation system as a whole, monitoring the impact of changes in resistance or fan characteristics on ventilation system, as well as analysis of individual incidents impact on the entire system or a significant part of it. However, with this method, it is very difficult to gain insight into changes that occur in narrow area, and to consider changes that occur within the mine workings. CFD simulation enables very detailed analyzes of changes in characteristic quantities in mine workings with impressive details and coverage of a numerous influences [8]. However, the CFD method makes it very difficult to cover most of the ventilation system or the entire coal mine. It would be very demanding to form a model for simulation, and it would be practically impossible to take into account all ventilation specifics, and the final calculation accuracy would be significantly determined by a large number of parameters on contact surfaces that need to be defined [5]. For the above reasons, these two methods are used in combination [13] since they complement each other. With CFD simulation, it is possible to present the different process phases and conditions very credibly where the process takes place, to calibrate simulation model with the actual state, and based on it to provide relevant data for simulation based on Hardy-Cross method. This paper represents research on possibility of applying simulation analysis as an integral part of ventilation system analysis and planning defense and rescue of people and property in crisis situations. Based on results of field measurements and laboratory
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analyzes, experimental calibration and verification of boundary conditions in realistic conditions of underground coal mines in B&H, a numerical model for computer simulation of contaminant distribution and changes in ventilation parameters is developed by Hardy-Cross method using VnetPC software package and CFD software package “Fluent” [6]. Computer model verification and validation is conducted based on the results of in-situ measurements and collected historical data [2].
2 Simulation Analysis of Ventilation System Failure The test site is an underground coal mine located in central Bosnia and was selected as a research site due to existing potential hazards. The pseudonym “A” was used instead of coal mine name, since this is a topic for which the public has a special sensibility, and in mine history, numerous accidents happened, some with severe consequences and human casualties. In accordance with the work program, “in-situ” research was performed by measuring ventilation parameters, sampling and analysis of coal samples, collecting data on gases, which is used as a basis for simulation analysis of characteristic ventilation system failures. The measurements were carried out in a special mode as not to jeopardize safety or a technological process. 2.1 Research Polygon “A” - Basic Characteristics and Laboratory Research Results Coal is exploited in two mines of Coal mine A (Mine 1 and Mine 2), and majority of production is carried out with two mechanized compatible longwalls. The mines are interconnected by a joint ventilation system and a joint conveyor for transporting rough coal out of the mine (Fig. 1). Both mines are classified as methane mines; when performing mining exploration works, opening and excavation, the occurrence of methane under pressure in the form of “blowers” is frequent, and the exploitation is followed by permanent methane extraction from the layer and accompanying deposits. Coal mine A is ventilated with two main fans and three main air inlets, and functions organizationally as two separate mines, which are connected by a joint outlet to the main transport system (Fig. 1). Such multi-fan ventilation system is characterized by the evident mutual influence of main fans, significant influence of natural conditions changes on ventilation, and increased risk for worker safety in case of ventilation failure in any of the ventilation section: whether it is a change in volume flow and air velocity or occurance of explosive, suffocating or poisonous gases. Long roadways, difficult communication with workers in the event of an accident and the lack of safety chambers [7] for their temporary evacuation result in danger to lives, even if personal protective equipment such as filtering or isolating “self-rescuers” are being used. There is a risk of exogenous fire in the coal mine entrance area and rooms of the intake airway. Sudden structure collapse can be caused by inconsistent application of
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Fig. 1. Mine A linear ventilation layout (normal air distribution)
the project and collapses have already been recorded in GTN (length 17 [m] and arch height 4–5 [m], as well as collapse of length 15 [m] height arch 1,2–4.5 [m]). Tests of coal dust showed values of the explosive characteristic Ek of 149.65 [bar/s] (Mine 1) and 164.5 [bar/s] (Mine 2), and the dust from both mines is therefore classified as explosively hazardous. Proximate analysis of coal samples from both mines determined the volatile matter of over 40%, which classifies this coal dust as explosive. The same analysis showed that the content of non-combustible matter in samples taken from both mines is less than 80% (ranging from about 23 ÷ 44% in Mine 1 and about 16 ÷ 18% in Mine 2) and from this point of view coal dust is explosive [14]. Analysis of coal propensity to spontaneous oxidation (Perhydrol method) showed that the coal on the longwall in Mine 1 is very prepared for spontaneous combustion and its further analysis determined minimum ignition temperature of the 5 [mm] dust layer was 240 [°C] and the minimum dust clouds (dust-air mixture) ignition temperature of 580 [°C]. Only one tested sample from Mine 2 had results that place it in the category of moderatelly prone to spontaneous combustion, while remaining two samples fall into the category of not prone to spontaneous heating. The tests results and analysis, as well as collected data on gases served as a basis for a simulation analysis of representative cases of ventilation failure in Mine A. 2.2 Computer Simulation In order to see the potential consequences of specific and possible failures on entire ventilation system function, a computer simulation of characteristic cases was performed on a previously calibrated model as follows: Fire in Mine 2, on a longwall where 0.1% (1000 [ppm]) CO is occured; Fire between Mine 1 and Mine 2 - room connecting 2 mines, which produces 0.95% of CO2 ; Fire at rooms of Mine 2, in which 0.03% (300 [ppm]) of CO is released; Fall in longwall of Mine 1 where the air flow is reduced to 20% compared to the initial state; Fall in GTN - Main transportation roadway (main entrance) where the flow was reduced to 10% of its initial value; Methane outburst in a concentration of 20% at the face heading of Mine 1; Large fire in GTN - in intake airway, with the release of a large amount of CO2 - simulated 7%; Fall in upcast airways towards the Mine 2 fan, flow reduced to 20% of the initial value.
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Simulation analysis determined ventilation branches in failure in case of simulated hazards. The contaminants distribution assesment and their intensity determined the zones where workers and production process are endangered. Concentrations of CO and CO2 gases used in oxidation processes simulation were obtained in real circumstances by chemical analysis of air samples taken from mine during oxidation process that took place in a longwall area in Mine A in 2015. During this oxidation, concentrations of carbon monoxide of 1040 [ppm] and carbon dioxide up to 15.06% in the fire zone were registered. Modified Hardy-Cross iterative procedure and calculations based on Navier-Stokes system of differential equations for method known as CFD application are two methods that are used in combination for this research, because they complement each other. 2.2.1 CFD Simulation of Oxidation Process Development Figure 2 shows a model for CFD simulation of oxidation process development and its influence in old workings behind a longwall. The picture shows an unfavorable layout of the mine workings. The lower room, which ends on the right side of the picture, is the main return airway stream, and has a direct connection with a slope from a parallel room that passes through the old workings, and is closed by an insulating brattice. However, despite this barrier, there is an impact of change and variation of fan depression in the old workings.
Fig. 2. Spatial layout of the longwall, old workings and surrounding rooms
The air comes to longwall through the lower transport roadway, which, as a path of fresh air current, is located a few meters above the lower main return airway. Due to coal seam slope and the rooms height difference, the oxidation process occurance leads to air heating and “thermal depression”, which manifests as a source of aerodynamic potential. Since there is an ascentional air flow at the longwall, the fire potential will not reduce the amount of air through longwall, and oxidation products are moving in three directions: (1) towards return airway and the longwall ventilation route; (2) towards the main room of the return airway under the longwall and (3) towards the main room of the return airway through the closed roadway, and towards the brattice. Combustion products moving this way go through rooms where there are no permanent workers. Figure 3(a) shows the static pressure levels. The workings with the highest absolute pressure potential (the lowest effect of fan depression) are marked in red, and the rooms
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(b)
Fig. 3. View of zones by: (a) static pressure level [Pa] between intake and return airways and (b) temperature [K] behind the longwall during oxidation process
with the lowest potential (the largest influence of fan depression) are marked in blue and green. Pressure differences in such ventilation system causes a high risk of air leakage, and pronounced coal tendency to spontaneous oxidation results in rapid development of the oxidation process [11]. Given the ascentional air flow, the pressure potential due to oxidation will not reduce the amount of air: neither in the longwall, nor through the old workings. In the first phase of oxidation process development, there is a hardly noticeable increased air amount through the longwall and a slight increase in the proportion of air that leaks through the old workings as a loss. Oxidation processes generate significant amounts of gaseous products, among whome CO and CO2 are especially important, and monitoring of absolute values and relative ratios (fire indicators) [4] of some other gases (CH4 , N2 , O2 ) gives a better insight into the state and dynamics of the oxidation process. Among the combustion products, it is especially important to monitor CO2 as a product of “complete combustion” and CO that is generated in oxidation conditions without sufficient oxygen [10]. Longwall position where oxidation occurs on the ventilation path is located just below one of the main fans. Pronounced “depression” effect of this fan in section results in increased air leakage between workings with different potential. The basic characteristics of oxidation processes in such conditions are: – Due to large pressure differences between the rooms of the horizonts or towards the atmosphere, air losses are increased, and uncontrolled air movement through the coal seam or old workings can propagate an intensive oxidation process in a short time. – The rise in temperature (Fig. 3b) and the increase of CO concentrations in workings is rapid, and in the phase of oxidation development until the appearance of open flame, most combustion products go through the return airway, where only a small number of workers can be endangered. 2.2.2 Simulation Analysis of Ventilation Parameters - VnetPC Some of the conducted simulations based on the Hardy-Cross method using the VnetPC package did not identify complex cases of ventilation risks and these situations are mainly foreseen by the Mine defense plan:
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– The first simulated fire in Mine 2 on a longwall where 0.1% CO is produced indicated contamination by combustion products only in the exit rooms behind the longwall on the air flow path. Such failure will not jeopardize the possibility of workers evacuation; – Although the second simulation of a fire in the room connecting two mines, producing 0.95% CO2 , indicates that oxidation in the connecting room would practically contaminate the entire west wing of the ventilation system, evacuation could be successfully completed with the full effect of protective equipment, if an adequate evacuation route is selected; – Simulation of fire at the room workings of Mine 2, producing 0.03% CO, indicated contamination of the area following ventilation path after the room (towards the main return airway and main fan), where evacuation can be performed safely; – The ventilation parameters obtained by the simulation of fall at longwall in Mine 1, where the air flow is reduced to 20% compared to the initial state, indicates that it will not cause serious consequences since only 19 branches had significant airflow decrease (up to 30%). Such a failure is considered partial because most of the mine ventilation is not interrupted. What should be taken into account in such situations is occurrence of potential secondary consequences due to oxidation intensification, and this type of failure should be viewed as a combination of increased oxidation, gas release and explosion hazard; – Simulation of fall in upcast airways towards the fan (Mine 2 - near the main fan) where the flow is reduced to 20% of the initial value results in an impact on almost entire ventilation system in such a way as to drastically change the flow - over 50% (20% simulated) occurs in 135 branches and in 6 branches to complete interruption in 144 to decrease, in 98 branches the flow is increased, while only in 6 remained unchanged. Despite such pronounced consequences, the planned routes for the workers withdrawal will not be endangered. The secondary consequence of such collapse may be that due to a large drop in air flow there is an increase in the concentration of methane and other harmful gases [9]. Particularly dangerous failures are the fall in the main transport roadway (GTN), the sudden methane outburst at face heading and the large fire in the GTN (intake airway), which are described below. Figure 4 shows ventilation system with the calculation of volumetric flows for simulated material collapse in roadway of main intake airway - the main transportation roadway (main entrance) where the flow was reduced to 10% of its initial value. This situation is based on two similar accidents that occurred in Mine A in May 2006 and then in 2007. This type of failure practically affects the ventilation system as a whole. In all branches there was a significant change in flow (different colors indicate changes) and in most cases there was a decrease in flow and only in 22 branches there was an increase, while there was a complete interruption of flow in 6 branches. While all produced coal comes out of the mine through this roadway, the main intake airway is in the opposite direction, which makes up the majority of the air in mine workings. In addition to transport lines, this roadway is the entrance for the main power supply, drainage, water supply, communication, etc., and accidents that occur here can lead to disruption of other systems crucial for the mine operation and people
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Fig. 4. Simulation of fall in GTN
rescue. The GTN is used to transport people entering or leaving the mine, so that is the main workers evacuation direction. Reduction or cessation of air flow, in the case when methane and other harmful gases are still emitted into the mine atmosphere, results in rapid endangerment of workers in most mine workings [1]. It is a very complex situation and it is extremely complicated to effectively manage the movement of endangered workers and their evacuation. On the other hand, as a favorable circumstance can be considered the fact that the endangered area can be easily reached from the surface on the free side, and very quickly and efficiently used technical means for rapid ventilation airways unblocking. Figure 5 shows simulated methane concentration in case of sudden release of large amounts of methane at face heading in Mine 1, so that at the time of outburst methane concentration at the site is 20%, and further concentrations depend on mixing with fresh air and have values in different branches of 19%, 15%, 13% and 12%.
Branches in which CH4 presence was detected
Fig. 5. Simulation of methane outburst at face heading of Mine 1
As Fig. 5 shows there will be increased concentrations of methane only in workings that are behind in terms of ventilation, ie the direction of methane movement will be by the path of return airway. Simulation results indicated presence of explosive concentrations at large lengths, so the risk of methane ignition is extremely high. In case of fire, it is possible
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to control gases concentrations by chemical analysis and monitor with instruments, while in case of methane and coal dust explosions, that is not possible. A coal dust explosion consumes all the oxygen and a consequence is formation of 6–8% CO (tests conducted in Poland) in that area. The methane explosion causes collapse of the workings, the rupture of high-voltage cables and the swirling up of coal dust.
Branches in which the presence of CO2 in maximum concentrations was detected
Fig. 6. Simulation of a fire in GTN
Figure 6 shows the CO2 concentrations in mine workings after simulated fire (conveyor belt burning) in the main transport roadway, where 3.7318 m3 /s of CO2 is released into the mine air during combustion process, with a concentration of 7% in this room. According to ventilation calculation results for this failure, the CO2 flow was recorded in 215 branches and in 159 undiluted in the maximum concentration, while only in 33 branches there was no carbon dioxide flow. In this situation, only the use of insulating self-rescuers with chemically bound oxygen (independent of the surrounding air) leaves the possibility for evacuation from such an atmosphere. The limiting circumstance is their time-protective effect. Since Mine A is equipped with insulating self-rescuers, the preconditions for a successful evacuation are more favorable. Significantly, in most mine workings affected by combustion gases, the CO2 concentration is approximately equal to the simulated 7%. This is due to the fact that the fire occurs in the room through which most of the ventilation air enters.
3 Conclusion This paper analyzes experiences with accidents in coal mines based on available data from the literature and experiences, and presents the key sources of endangering the health and lives of workers in isolated areas due to oxidation processes, materials fall, rock burst and gas or dust outburst in mine workings. Simulation analysis of the ventilation systems failure mechanism using Hardy-Cross and CFD methods identified ventilation branches that failed in cases of simulated hazards, determined the air flow, pressure losses, temperature, methane concentration and general distribution of contaminants and their intensity in individual ventilation system
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branches. This way, hazards were identified, as well as the probability of failure in certain parts of ventilation system, and based on that clearly defined zones where workers are endangered as well as their exposure to dangerous conditions in terms of time, type and intensity of contamination during failure. The simulation analysis proposed in this paper enables different scenarios for potential hazards testing, prediction of secondary ventilation system failures, and the information obtained this way enables planning based on specific indicators and implementation of measures and decision-making in crisis situations on scientifically based grounds. Since it is very difficult to faithfully make a model for CFD simulation that would take into account all the specifics of the coal seam, space shapes, local conditions, etc., the accuracy of CFD simulation is limited, but with a certain level of simplification can be a significant addition to conventional procedures. CFD models indicate potential ventilation risks, key advantages and disadvantages of certain technical solution variants. By combining the application of CFD simulation for confined spaces (domains) and conventional calculation based on the Hardy-Cross method, it is possible to determine the ventilation system behavior and ventilation risks in a wide range of parameter variations. The paper presents a pilot project of a network model for simulation analysis of ventilation conditions, developed methodology for prognostic simulation of ventilation failure consequences in isolated mine workings, and developed model for hazard identification and risk assessment for human health and life due to ventilation failure. As a result of the research, a new methodology in safety planning and management in coal mining can be established, which provides conditions for survival and evacuation of workers blocked in underground mines during mining accidents. The shortcomings of the conducted research arise from objective limiting factors, multidisciplinary research topics and analysis in the sphere of traditionally conservative area of mineral production. The distinctly stochastic nature of underground coal exploitation process, where it is practically impossible to predict all, is a serious shortcoming of this, but also of most researches related to underground coal mining.
References 1. Kelsey, A., Lea, C.J., Lowndes, I.S., Whittles, D.T., Ren. X.: CFD modelling of methane movement in mines.In: Proceedings of the 30th International Conference of Safety in Mines Research Institutes, South African Institute of Mining and Metallurgy, pp. 475–486 (2003) 2. Wala, A.M., Vytla, S., Taylor, C.D., Huang, G.: Mine face ventilation: a comparison of CFD results against benchmark experiments for the CFD code validation. NIOSH, Min Eng. 59(10), 49–55 (2007) 3. Kher, A.A., Yerpude, R.R.: Modeling accident data for decision support in underground coal mines. Int. J. Eng. Res. Technol. (IJERT) 3(7), 654–657 (2014) 4. Dhillon, B.S.: Mine Safety, A Modern Approach. Springer, London (2010) 5. Deli´c, E., Baši´c, A., Šiši´c, R.: Case study of CFD simulation in mining accident investigation. In: 11th U.S./North American Mine Ventilation Symposium; The Pennsylvania State University, SAD: 491–499 (2006) 6. Nuki´c, E.: Procjena rizika otkaza elemenata ventilacionog sistema u izolovanim prostorijama podzemnih rudnika uglja: doktorska disertacija. Univerzitet “Džemal Bijedi´c” u Mostaru (2017)
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7. Li, F., Jin, L., Han, H., Wang, Y.: Study on new emergency refuge chamber of coalmine underground. Res. J. Appl. Sci., Eng. Technol. 5(19), 4762–4768 (2013) 8. Yeoh, G., Yuen, K.: Computational Fluid Dynamics in Fire Engineering (Theory, Modelling and Practice). Elsevier Inc., USA (2009) 9. Cheng, J., Zhou, F., Yang, S.: A reliability allocation model and application in designing a mine ventilation system. IJST Trans. Civ. Eng. 38(C1), 61–73 (2014) 10. Yuan, L., Smith, A.: CO and CO2 Emissions from spontaneous heating of coal under different ventilation rates. Int. J. Coal Geol. 88(1), 24–30 (2011) 11. McPherson, M.J.: Subsurface Ventilation and Environmental Engineering. Chapman & Hall (1993) 12. Law on the Mining Industry of the Federation of Bosnia and Herzegovina, Official Gazette of the Federation of B&H No. 26/10 13. Diego, I., Torno, S., Toraño, J., Menéndez, M., Gent, M.: Tunnelling and Underground Space Technology, pp. 189–200. Elsevier Ltd. (2011) 14. Rules on contents, methods and procedures for classification and categorization of coal seam and coal mine by the hazards of explosive coal dust, Official Gazette of the Federation of B&H No. 104/13
Influence of the Human Body’s Center of Gravity on Some Aspects of Lower Limb Movement During CAD Modeling Sydorenko Ihor(B) , Tonkonogyi Volodymyr, Bovnegra Liubov, Salii Vera, and Kovban Sofia Institute of Industrial Technologies, Design and Management, Odessa National Polytechnic University, Shevchenko Ave 1, Odessa 65044, Ukraine
Abstract. In biomechanics, the determination of the center of gravity of the human body has always been an important part of many biomechanical studies, which were aimed at determining the factors of external forces acting on the elements of prostheses necessary for their construction, and predicting their durability. Since at present the design of these products is usually carried out in CAD, it is relevant to create analytical methods for determining this parameter. The article presents a method for determining the center of gravity of a human body, in which body parts are considered not just as a three-dimensional object of the main geometric forms of constant density, but as an “assembly” object that defines a three-dimensional object of variable density. The block diagram of the software implementation of the proposed method is presented. Mathematical modeling has been carried out, the results of which indicate a sufficiently high accuracy of the presented method. Ways to improve its accuracy are indicated. Keywords: Center of gravity of the human body · Three-dimensional object with variable density · Three-dimensional object with constant density · Segmentation method · Dynamic characteristics
1 Introduction At present, solving the problem of determining the center of gravity of the human body requires an increase in the accuracy of such calculations, since the technical development of society leads to the creation of mechanical devices that, being located on the human body, increase its physical capabilities. These devices, in the form of orthoses located on the limbs, or an exoskeleton, transform a person into a biomechanical system. Considering that the development of such systems is increasingly carried out with the involvement of CAD, the determination of the center of gravity of a biomechanical system in these environments becomes even more relevant, since this indicator affects the dynamic properties of the system under consideration.
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 385–393, 2021. https://doi.org/10.1007/978-3-030-75275-0_43
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2 Theoretical Research Turning to the consideration of the mechanical properties of biological tissues, it should be noted the main features of their mechanical properties, which is as follows - most biological tissues are anisotropic. It follows from this that their physical, including mechanical properties are not the same in different directions, which is due to their heterogeneous structure, in which muscle and bone tissue are clearly distinguished. In a number of applied automatic design systems there are tools for calculating the center of gravity of solids, but their use does not always give the correct result when used for objects of biological nature. One of the rather important problems that is important to solve in computer-aided design systems is the problem of determining the center of gravity of a biological object, for a software solution of which it is necessary to develop an appropriate algorithm. 2.1 Literature Review The analysis of the methods for determining the center of gravity of the human body made it possible to establish the following. Determination of the position of the center of gravity of the body is currently carried out either experimentally and analytically, by measuring directly from the human body [1], or analytically [2]. There are several, both experimental - analytical, and analytical methods, which are called the segmentation method. Thus, when using the experimental analytical method used by the National Aeronautics Administration [3], it is believed that the center of gravity of the human body is located depending on the position of individual body parts characterized by different mass, density and different static moments of mass [4, 5]. In this case, the human body is divided into 14 separate segments (Fig. 1a). On the segmental model, there are 0 - trunk, 1 - head, 2 and 3 - forearms, 4 and 5 - shoulders, 6 and 7 - arms, 8 and 9 - thighs, 10 and 11 - legs, 12 and 13 - feet [6, 7]. The segmentation of the human body adopted in this case requires that the length li , the mass and the local position of the center of gravity be attributed to each individual segment of the body. According to this segmentation method, each body segment can be replaced by an axisymmetric body. Consequently, the center of gravity of the i-th segment is located at some distance ki , expressed as a percentage, on the axis of symmetry of the li segment. The location of the centers of gravity and the moments of the segments in this experimental - analytical method were obtained experimentally on the basis of measurements carried out on a group of 13 corpses [8]. To obtain more accurate results in further analysis, the segment model was additionally supplemented with two other dimensions: arm span R and hip span B. It is assumed that the global frame of reference (X0, Y0, Z0) begins at the beginning of the main segment, and for the rest of the segments of the body frame, starting from the joints connecting them with the previous ones. To facilitate the measurement of joint flexion angles and to adopt an additional method of obtaining data from photographs, the human body can be projected in various positions on the 3 planes of the global reference system (X0Y0, Z0Y0, X0Z0). Another method, which is positioned as analytical, and more suitable for its use in computer-aided design systems, is as follows, the human body is also segmented into
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14 elements, which are three-dimensional objects of basic geometric shapes or their combination (Fig. 1b).
Fig.1. Methods for segmentation of the human body in determining its center of gravity: experimental - analytical (a); analytical (b)
Thus, the arm and head according to this technique are defined as ellipsoids of rotation (ER), and other body segments are defined as variations of the elliptical body. For example, the truncated cone (TCC) for the forearm, shoulder and lower leg, the elliptical column (EC) for the upper and lower torso, the foot, the cone-shaped elliptical body (ES) for the mid-torso, and elliptical bodies with one round end for the foot and thigh. The determination of the mass of each segment is made according to anthropometric data, which express the weight of the segment as a percentage of the total body weight, and its center of gravity is located in the middle of the segment. It should be noted that the presented methods are generalized and do not provide complete information about the individual characteristics of the modeled biological individual, namely about his physical development and state, as well as the presence of other individual characteristics. 2.2 Research Methodology To solve the problem of determining the center of gravity of the human body or its individual parts, taking into account the existing individual characteristics, a software module has been developed in the Autodesk Inventor CAD system based on the further development of the previously presented experimental - analytical segmentation method. A feature of the proposed method for determining the center of gravity is as follows. Each of the selected 14 segments of the human body is considered not just as a threedimensional object of basic geometric forms of constant density, but as an “assembly” object that defines a three-dimensional object with variable density (Fig. 2). Variable density is determined by the data on the density of bone and muscle tissue (ρbone and ρmuscle ) of various parts of the human body, which are obtained on the basis of the corresponding results of medical research [8, 9]. Data on the density of bone and muscle tissue of various elements of the human body, depending on gender, age,
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past diseases and general physical condition of a person, are summarized in external specialized databases.
Fig. 2. Modeling in CAD of segment 3 “forearm” as an object “assembly” with variable density: modeling of muscle tissue (a); modeling bone tissue (b); forearm assembly model (c)
The use of certain algorithms for processing such databases and transferring the processing results to the CAD environment allows the proposed method for determining the center of gravity of a person to be positioned as analytical. The generalized block diagram of the program, developed according to the proposed methodology, makes it possible to distinguish the following stages of its work (Fig. 3). The first stage is the initialization process, during which initial values are set or program variables are set to zero before the program is executed. At the second stage, all data about the individual to be modeled are entered manually. The data are divided into five subgroups: anthropometric data (in addition to manual measurement and input, these data can be obtained by photographing an object against the background of a measuring grid and corresponding post-processing), gender, age, physical condition of a person and his state of health. Anthropometric data include such key parameters of the human body as weight, height, width of the shoulder girdle, total length of limbs (segments) and their components, etc. For an objective assessment of the physical condition, algorithms for determining body mass indicators were used, as well as an assessment of physique. Depending on the results obtained, the indicator of physical condition is determined on a scale from 1 to 6, which, together with the indicator of age, makes it possible to establish the density of bone and muscle tissue (ρbone and ρmuscles ). An additional assessment of health, taking into account the presence or absence of diseases of the musculoskeletal system and their residual or current impact on the state of health, makes it possible to clarify these indicators. In the absence of identity between the initial data and the data in specialized databases, the missing indicator is determined by spline interpolation according to the data available in the databases. At the third stage, the input data is processed, during which the physical and mechanical properties of the model materials, 2D or 3D sketches are formed, which determine the kinematic structure of the object and the shaping of the segments of the object under consideration. In this case, the area of admissible changes in the shape and position of the modeled segments and the nature of their functional interaction is determined. At the fourth stage, the program branches out, depending on the variant of the required solution.
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Fig. 3. Block diagram for calculating the center of gravity of a biological object as an assembly with variable density.
The first block of this stage implements the determination of the center of gravity of the local part of the model to which the user pointed. The second block of this one implements the determination of the general center of gravity of the model. In the first two blocks that define static modeling, the result is visualized as a superposition of a 3D point defining the center of gravity on the model body, indicating its exact coordinates in the global reference system (X0, Y0, Z0), which starts at the beginning of the main segment, and for the rest of the segments - starting with the joints connecting them with the previous ones (it is possible to determine the coordinates of the center of gravity in relation to the reference system adopted by the user). Moreover, this point can be located both inside the model and outside it. In the third block of the fourth stage, the determination of the coordinates of the general center of gravity of the model in dynamics is implemented. In this case, in a given range of segment displacement with a specified step, the total center of gravity is calculated. The result of the work of the third block of the program is a 3D trajectory of the displacement of the general center of gravity of the model in relation to either the global or the user-accepted frame of reference. The segment center-of-mass coordinates are also available. At the last stage of the program, it is possible to return to data entry and correct them, or to terminate the work. 2.3 Results To assess the influence of the coordinates of the center of gravity of a biological object on its dynamic characteristics, the corresponding mathematical modeling was carried out. A well-known mathematical model was used that describes some aspects of movement
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Fig. 4. Calculation scheme to the accepted mathematical: generalized (a); used in calculations (b)
of the lower limb with a horizontal position of the human body on a flat surface [10]. In this case, the position of the lower extremity is represented in a certain OXY plane, which is parallel to the sagittal plane passing through the femoral head, taken as the origin (Fig. 4a). The centers of the knee and ankle joints are represented by the corresponding joints A and B. The heel B is assumed to slide along a horizontal guide. Modeling assumes that at some points of the limb, in addition to gravity, external forces Fk , k = 1… n can be applied in the form of gravity forces of additional payloads, as well as elastic and dissipative forces from springs and dampers in orthoses. The force factors associated with sliding B are presented in the form of friction forces Ff and normal force N based on the principle of release from constraints, since the lower limb in this case can be considered as a flat mechanical system with three degrees of freedom. The size of the shoulders and the direction of the muscles m. iliopsoas and m. gluteus maximus, assuming their straightness, are determined by the coordinates of the centers of the areas of their attachment to the femur and ilium [7]. The reactions in the joints are determined from the kinetostatic equations compiled for the limb as a whole and the thigh and lower leg separately. The used mathematical model allows at each moment of movement to determine three articular reactions R1 , R2 , R3 , three moments M1 , M2 , M3 and three efforts of muscles T1 , T2 , T3 . The sign of the moment of muscle effort in the joint indicates the muscle that is currently active, for example, if M1 > 0, then muscle is active m. iliopsoas. Using this mathematical model, a comparative analysis of efforts in the muscles of the hip group m. iliopsoas and m. gluteus maximus (T1 ), the reaction of the pelvis R1 and the moments of muscle effort in the hip joint (M1 ) for a given law of motion of the thigh ϕ (t). Simulation was carried out for two cases. In the first case, the coordinates of the centers of gravity of the extremities were determined according to the analytical method (Fig. 4a), in the second, according to the proposed one (Fig. 4b). The presence of external forces and forces of inertia in the system was not considered. Effort T1 of muscle m. iliopsoas is attached at the origin O after bringing it to that center. It is accepted that the foot does not move relative to the lower leg υ = const (90°). The mass-inertial characteristics of the systems for each of the calculations are presented in Table 1. It should be noted that the positions of the centers of gravity of the segments and their masses, determined by the proposed method, correlate very well with the positions
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Table 1. Mass-inertial characteristics of the human lower limb №
Parameter (designation, units)
Segmentation technique Analytical
The proposed
1
Thigh length (L0A , m)
0,43
0,43
2
Shin length (LAB , m)
0,37
0,37
3
Foot length (LBD , m)
0,24
0,24
4
Thigh mass (m1 , kg)
8
7,68
5
Shin mass (m2 , kg)
2,5
2,42
6
Foot mass (m3 , kg)
0,74
0,24
7
Thigh center of gravity (L0C1 , m)
0,5 L0A
0,36 L0A
8
Shin center of gravity (LAC2 , m)
0,5 LAB
0,35LAB
9
Foot center of gravity (LBC3 , m)
0,5 LBD
0,35 LBD
Coefficient of friction of the heel of the foot
0,2
0,2
10
of the centers of gravity determined by the previously presented experimental-analytical method of segmentation. According to the available average statistical data, the movement of the thigh was considered as periodic in the interval ϕ = 0… 60° with a period of 2τ (τ - the time of movement of the thigh between the extreme positions is taken equal to 5 s). Hip motion law 2 3 t t t (1) ϕ = ϕ0 + (ϕτ − ϕ0 ) 10 − 15 + 6 τ τ τ where ϕ0 = 0, ϕτ = 60° when the hip moves up and ϕ0 = 60° ϕτ = 0° when moving down. The law of motion (1) has two properties: the speed and acceleration of the hip in the extreme positions are equal to zero, which determines the following initial conditions. (2) ϕ(t) = ϕ(t) ˙ = ϕ(t) ¨ t=0,τ =t = 0 Conditions (2) define the movement of the hip as “soft”, since when the direction of movement of the limb is changed, there are no inertial overloads that cause pain, which facilitates the task of performing such a movement. Graphical interpretation of one of the calculation results, namely the change in the moment of the muscles of the hip joint M1 when the limb moves up and down when using various methods for determining the centers of gravity of body segments are shown in Fig. 5. Analysis of the calculated values shows that only the flexors (m. Iliopsoas) are involved in the movement of the lower limb from the muscles of the hip group, contracting when lifting the hip and slightly reducing their tone when lowering. When the hip moves up, the total moment of efforts of the muscles of the hip joint is somewhat greater than
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during the reverse movement. This is due to the contribution to the movement of the hip by the gravity forces of the limb segments. The magnitude of the pelvic pressure force on the femoral head practically does not change when the direction of movement of the limb is changed.
Fig. 5. Changes in the moment of the muscles of the hip joint: calculation of the center of gravity of body segments according to the analytical method (a); calculation of the centers of gravity of the segments according to the proposed method (b)
3 Conclusion According to the results of the research, it was found that, depending on the use of a particular method for determining the coordinates of the center of gravity of a biological object, the results of the dynamic calculations carried out differ by 15… 18%. Considering that these results were obtained with a “soft” movement of the hip, without taking into account external forces and forces of inertia, it should be recognized that this error will only increase when the law of motion changes and the system under consideration is supplemented with other forces. Proceeding from the fact that the positions of the centers of gravity of the segments and their masses, determined by the proposed method, correlate very well with the positions of the centers of gravity determined by the experimental analytical method of segmentation, its adequacy to real objects is quite obvious. The accuracy of determining the coordinates of the centers of mass by the proposed method can be increased by expanding specialized databases based on the results of medical research.
References 1. Tilley, A.R.: The Measure of Man and Woman: Human Factors in Design. Wiley, New York (1993) 2. Rao, S.S., Bontrager, E.L., Gronley, J.K., Newsam, C.J., Perry, J.: Three-dimensional kinematics of wheelchair propulsion. IEEE Trans. Rehabil. Eng. 4(3), 152–160 (1996) 3. Arampatzis, A.A.: Mathematical high bar-human body model for analyzing and interpreting mechanical-energetic processes on the high bar. J. Biomech. 31, 1083–1092 (2012)
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Optimization and Yield of Low Quality and Small Sized Diameter Oak (Quercus robur L.) Logs in Production of Rough Elements Selver Smaji´c1(B) , Juraj Jovanovi´c2 , Josip Ištvani´c2 , and Murˇco Obu´cina3 1 Tamex doo, SenadaPoturakSenˇci, 27b, 71000 Sarajevo, Bosnia and Herzegovina 2 Faculty of Foresty, University of Zagreb, 10000 Zagreb, Croatia 3 Mechanical Engineering Faculty, University of Sarajevo, 71000 Sarajevo,
Bosnia and Herzegovina
Abstract. It is not usual practice but sometimes without previous agreement, to sawmills sometimes are delivered logs which do not fit regulations for standard saw logs. Often those logs are below standard quality or dimensions. Namely, sawmills compensate the lack of standard saw logs, in aspiration to fully use own capacities, by processing round wood with smaller dimensions called thin round wood. Research aim of this paper was to determine volume yield, lumber value yield and log value yield of Oak (Quercus roburL.) logs with smaller diameter and quality during their processing dimension stock and flooring components. The object of research were Oak logs divided into three groups with mid diameter ranging from 18 to 20, 21 to 23 and 24 to 26 cm. Primary sawing of logs was performed by using live sawing technique on long band saw. All obtained sawn boards were sawn up into dimension stock and flooring components by cross – rip sawing method. The best log volume yield in the form of dimension stock and flooring components showed logs with mid diameter ranging from 24 to 26 cm, followed by logs with diameter from 21 to 23 cm, and logs with diameter from 18 to 20 cm, with mutual insignificant difference. Results show that the best quality dimension stock and flooring components were sawn from logs with mid diameter ranging from 21 to 23 cm, followed by logs with diameter from 24 to 26 cm, and logs with diameter from 18 to 20 cm. The best log value yield results showed logs with mid diameter ranging from 24 to 26 cm, followed by logs with diameter from 21 to 23 cm, and logs with diameter from 18 to 20 cm. In this paper the usage of three very confined diameter groups was compared. It was determined that there is slight but insignificant mutual difference. Keywords: Oak (Quercus roburL.) · Low quality and small-sized diameter logs · Sawmilling production · Dimension stock · Log volume yield · Lumber value yield · Log value yield
1 Introduction One of the most used and most important wood species in Europe is Oak. The yield of raw material, as well as the quality and dimensional structure of sawn products, © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 I. Karabegovi´c (Ed.): NT 2021, LNNS 233, pp. 394–400, 2021. https://doi.org/10.1007/978-3-030-75275-0_44
Optimization and Yield of Low Quality and Small Sized Diameter Oak
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depends on the method of sawing (Zubˇcevi´c 1973). Also the quality of raw material is the most important factor for yield of logs (Petutschnigg and Katz 2005; Šoški´c and Mili´c 2005). The dimensions of the log (Tanušev et al. 2009) also is important for yield. Processing of the Oak logs is not often usually carried out on log band saws (Fig. 1). Mostly often live sawing is applied on the primary machine, and the separation is done on rip saw machines. In general the yield of raw material, as well as the quality and dimensional structure od sawn products, depends on method od sawing (Skaki´c 1985). The due complicated process of sawing on the log band saw it is necessary to analyze and measure duration of each partial operations of the sawing process (Vukiˇcevi´c 1989). Processed log volume, whose increase also increases the saw capacity, has the most significant effect on the long band saw capacity (Ištvani´c et al. 2009). Research aim of this paper was to determine volume yield, lumber value yield and log value yield of Oak (Quercus robur L.) logs with smaller diameter.
Fig. 1. Automatized line with log band saw
2 Material and Methods The oak sawlogs, 18–20, 21–23 and 24–26 cm in diameter and 1,5–2,5 m length class, were used in this research. Every logs was chosen according to HRNEN 1316-1, 2012 and belong to III class od logs. They were separated in three groups, 18–20 cm, 21– 23 cm and 24–26 cm, made from 30 logs of and prepared for live method of sawing.Those groups were almost the same, regarding the log quality and dimensions.Measurements taken were: length of log (l), diameters (thin end - d, mid length – dm, thick end - D). Values of diameters were calculated as the mean value of two crossmeasurements. All dimensions were rounded to the nearest centimeter. The volume of bark was calculated as the difference between volumes of each log with and without bark. Primary sawing was carried out on automatized production line with log band saw (Primultini SHF1371515,
396
S. Smaji´c et al.
flywheels diameter 1400 mm). Logs were sawn into 25 and 38 mm thick wood products, for group 18–20 cm, and 25 mm and 50 mm for groups of 21–23 cm and 24–26 cm of logs diameter. It was sawn parallel to the central log axis, with a thin end forward. Blade parameters were: width - 206 mm (band saw) and 90 mm (band resaw), thickness – 1.20 mm (band saw) and 1.0 mm (band resaw), and breadth of swage set on one side: – 0.3 mm (for both blades). Secondary sawing was carried out by the cut-first process on machines with individual cuts, and smaller products were made on a band saw and a cross cut saw. With the exception of sawdust, all wood waste was collected and the mass was measured (precision of 0,2 kg). Live sawing were used as the sawing patterns (Fig. 2). Volume of logs without bark (Vl) was calculated according to the formula (1): Vl =
d +dm +D 3
4
2
π
·l
(1)
Sawing pattern was not predefined but it was adapted according to quality, dimensions and shapes of logs. The main goal of processing was to make products of the highest quality and highest possible value.
Fig. 2. Sawing patterns for Oak logs-live sawing
Un-edged and half edged sawn boards, long and short edged sawn boards, as well as small products, elements for flooring strips and squares were produced. Standard applied in this process were HRN EN 975-1. The thicknesses of the boards were 25, 38 and 50 mm. Dimensions of products were measured with the precision of 5,00 mm, then they were calculated to standard values and the difference in volume was used to determine the actual oversize. Different kind of products, which were produced are presented by Fig. 3. The quantitative yield was calculated by dividing the volume of sawmil products by the volume of logs without bark. Analysis of the sawmil product structure was done for each group of products (unedged and edged sawn boards and small sawn wood products), calculated as the share in the total volume of products. Due to its irregular shape, the total volume of large wood waste (slabs, edgings and trimmings) was calculated as a ratio of waste wood mass and wood density. Average wood density was calculated based on five randomly chosen products from each log, by measuring their mass and dimensions. The volume of sawdust was obtained as a difference between the log volume and sum of product volume and large wood waste volume. Quantitative yield is a very important indicator of sawmill processing success,
Optimization and Yield of Low Quality and Small Sized Diameter Oak
A
B
397
C
Fig. 3. A-Un-edged and half edged sawn boards, B-Edged and half edged sawn boards C-Small woodproducts (elements for flooring strips and squares)
but the objective assessment of the effects of production is often made by the value yield. This is often calculated by using the value of production, expressed in a currency per unit of the area or volume (Shepley et al. 2004). This is a simple and practical method and it was used as one of the indicators of value yield in this research. Factors that can be included in the calculation of value yield and which in this research used were: cvi – coefficient of value increase – measure of value yield; cqy – coefficient of quantitative yield; cp – price coefficient – quotient of average prices of sawn boards and logs; cvt – mean coefficient of value of sawn boards – measure of real value of sawn boards, compared to a theoretic maximal value; cvl – coefficient of value of logs – measure of value of logs, compared to an average value; ccp – coefficient of complexity of processing – indirect indicator of the amount of work, determined by the ratio between the average product volume of each log and the average product volume of all logs. Calculation was done according to the formula 2 (Šoški´c and Popadi´c 2010): cvi =
cqy · cp · cvt · ccp cvl
(2)
3 Results and Discusion Structures of sawmill products made of Oaksaw logs is shown in Table 1. The data show quantitative yield of live sawing. The structure of quantity yield (%) depending on the used live method of sawing is shown also graphically (Fig. 4). However, in this research differences were not statistically confirmed due to high variation within the groups. Analysis of variance and descriptive statistics are shown in Table 2. Results showed that there is stastistically significant difference between sawedlogs, different dimensions and quality only between volume of the groups of logs. The cause for this can be in the fact that the logs had irregular shape and they had lower diameter. High variation between logs was found (coefficient of variation of sawdust was about 18,70%, and the large waste was 19,33%).
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S. Smaji´c et al. Table 1. Structure of quantitative yield (%) based on the used method of sawing Wood products
Live [%]
Un-edged boards
18,51
Half edged boards
0,00
Total, un-edged and half-edged wood
18,51
Edged boards L < 2 m
10,57
Total, edged wood
10,57
Small wood products elements, flooring strips, squares 24,71 Raw material yield
51,77
Large waste
19,33
Sawdust
18,70
Total Waste
36,01
Oversize
8,65
Total
100,00
Yield of products based on live method of Oak logs sawing 25.00 [%]
20.00 15.00 10.00 5.00 0.00 Un-edged Half edged boards boards
Edged boards L